•••• Full Contents List of Figures List of Tables

Full Contents
List of Figures
List of Tables
Maintaining a Safe Environment
Introduction: A safe environment as an activity of daily living
Living processes
The environment
Homeostasis and health: Linking the external and internal environments
Levels of organisation
The biology of life
Anatomical orientation: Cavities and the organisation of the body
Conclusion: Maintaining a safe environment
Chapter summary
Working and Playing
Introduction: Working and playing as activities of daily living
Levels of organisation
Chemicals: Energy and reactions
Energy and ATP
Conclusion: Working and playing
Chapter summary
Growing and Developing
Introduction: Growing and developing as activities of daily living
The external environment
The internal environment
Why we grow and develop
Our foundations: Structure and function
Inheritance: Translation, transcription, replication and the genetic code
The reproductive system
Development and differentiation
Stem cells
Lifespan changes
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Conclusion: Growing and developing
Chapter summary
Introduction: Communicating as an activity of daily living
The environment
The nervous system
Organisation of the nervous system
Cellular communication
The endocrine system
Changes during lifespan and lifestyle
Conclusion: Communicating
Chapter summary
Controlling and Repairing
Introduction: Controlling and repairing as activities of daily living
The environment
Why we control body temperature
Metabolism and thermoregulation
Biology and homeostasis
The skin as an example of control of repair and growth
Changes during lifespan and lifestyle
Conclusion: Controlling and repairing
Chapter summary
Introduction: Moving as an activity of daily living
The environment
Mobility and movement
The skeletal system: Bones and joints
The muscle system
Energy for movement
Types of movement
Changes during lifespan and lifestyle
Conclusion: Moving
Chapter summary
Introduction: Breathing as an activity of daily living
The environment
The respiratory (pulmonary) system
Changes during lifespan and lifestyle
Conclusion: Breathing
Chapter summary
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Introduction: Transporting as an activity of daily living
The environment
The blood system
The lymphatic system
The cardiovascular system
The vascular system: Blood vessels
Changes during lifespan and lifestyle
Conclusion: Transporting
Chapter summary
Eating and Drinking
Introduction: Eating and drinking as an activity of daily living
The environment
Food and nutrients
Metabolism and calorie requirements
Changes during lifespan and lifestyle
Conclusion: Eating and drinking
Chapter summary
Introduction: Eliminating as an activity of daily living
The environment
Elimination from the bowel
Elimination from the kidneys
How waste is removed from the bladder
Changes during lifespan and lifestyle
Conclusion: Eliminating
Chapter summary
Cleansing and Dressing
Introduction: Cleansing and dressing as activities of daily living
The environment
The immune system
Detection and prevention of infections
The innate immune system and response
The adaptive immune system and response
Changes during lifespan and lifestyle
Conclusion: Cleansing and dressing
Chapter summary
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Sleeping and Healing
Introduction: Sleeping and healing as activities of daily living
The environment
Sleeping and dreaming
Changes during lifespan
The Gate Theory
Conclusion: Sleeping and healing
Chapter summary
Introduction: Dying as an activity of daily living
The environment
Population numbers
Death and dying: Biological aspects
The nature and causation of disease
Conclusion: Dying
Chapter summary
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Maintaining a
Safe Environment
Chapter Outline
Introduction: A safe environment as an activity of daily living
Living processes
The environment
Homeostasis and health: Linking the external and internal environments
Levels of organisation
The biology of life
Anatomical orientation: Cavities and the organisation of the body
Conclusion: Maintaining a safe environment
Chapter summary
Introduction: A safe environment
as an activity of daily living
Much is made nowadays of Health and Safety.
There is legislation for it. There are experts in
it. There are courses on it. But do we actually
think about the link between these two words
health and safety and why we need to join
In 1888 the makers of matches in London
went on strike because of the disease they
were prone to: ‘phossy-jaw’, a disease that
turned their skins yellow and caused their
hair to be lost in a form of bone cancer. The
disease was caused by the phosphorous in the
matches they made. The match-girl strike was
a famous moment in Health and Safety policy
linking a safe work environment to health. In
the late nineteenth century boys were sent up
We are stardust,
We are golden,
We are billion year old carbon
And we’ve got to get ourselves
back to the garden.
Joni Mitchell* (1943–),
Canadian musician, songwriter
and painter
chimneys to sweep them clean and suffered
in later life from breathing problems and cancers. Workers were and are often bullied into
doing dangerous jobs and carrying out unsafe
practices. Health and Safety executives, while
often annoying to some of us, have been
instrumental in protecting all of us from bad
work practices.
We live in two environments: our insides –
what is beneath our skin – and the outside
world. These constitute our internal and external environments. For all of us to survive and
thrive and to be healthy we need a safe external environment. A safe external environment
is one which, amongst other things, provides
shelter from the elements, sustenance and
protection from infection in the form of clean
water and food, as well as some limits on traumatic events such as road or rail traffic accidents
and injuries from work.
Words and Music by JONI MITCHELL
Copyright © 1969 (Renewed) CRAZY CROW MUSIC
All Rights Administered by SONY/ATV MUSIC PUBLISHING,
8 Music Square West, Nashville, TN 37203
All Rights Reserved
Used by Permission
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All of these safety issues reflect our need to
maintain our biological selves against
infection and
environmental variables.
However, the external environment is not
always safe. What is it in our biology that makes
us all so vulnerable to damage and to the vagaries of the external world?
The body is made up of millions of small
units called cells. Cells can only exist in a very
narrow range of environments; they are intolerant of large or prolonged changes to the optimum conditions, also called variables, which a
cell can tolerate.
Health Connection
Work and environment
When a patient comes to a clinic
they are often asked as part of
their history what their job is. This
is because certain jobs are associated with certain diseases. All of a
person’s history may help to explain
and work out what is wrong with
the patient.
To survive they carry out a remarkable process:
they maintain their own internal environment
within a fairly narrow range of variables. This
maintenance is not done for the cells of the
organism; it is done by the cells. This process of
self-maintenance of internal variables and conditions is called homeostasis and is the basis of
all the physiological processes of the body, the
processes that the body carries out.
We have the ability to adjust internal conditions to remain within an environment tolerable for our cells. In ill health we often cannot
adjust our internal environment to maintain it
within the range that our cells can tolerate. If we
cannot return to a normal range for a variable it
may affect our cells to such an extent that they
die. If too many cells die, we die. Medical or
clinical intervention tries to adjust our internal
environment back to within normal ranges.
In this chapter some key concepts in biology
and health will be discussed. These include
This chapter links to Chapter 2, ‘Working and
Playing’, which
While cells are very sensitive to changes, in contrast living things, organisms, which are made
of cells, can exist in a fairly hostile environment.
internal and external environments and
biological organisation.
looks at some of the variables that must be
looks at the normal ranges for each variable;
introduces how each variable alters during
normal daily activities;
Box 1.1 Homeostasis
The word ‘homeostasis’ comes from the Greek:
HOMOIOS – means something that is like or similar to;
STASIS – means something that is standing or static.
So homeostasis (pronounced home-ee-oh-stay-sis) means trying to stay the same.
The human body needs to maintain the integrity of its
structure – or anatomy – what it is made of;
function – or physiology – what it does.
Homeostasis is the maintenance of a safe, optimum internal environment within a narrow range
for a number of conditions or variables in the face of fluctuating external environments. It is
carried out by physiological processes discussed below.
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introduces some of the clinical observations
and skills that are used to measure these
discusses links to homeostasis, health and
ill health.
These chapters act as an introduction to the
processes and mechanisms that will be discussed in detail in the later chapters.
Health Connection
Vital signs
Vital signs are internal conditions
that are measured by health care
professionals to ascertain whether a
patient is healthy, i.e. whether their
internal conditions are within the
normal range. See page 62 for a full
These biological living processes include
activities such as
excreting and
As mentioned above these are what healthy
independent living organisms do. So biology
and health are intimately linked.
In the health field these living processes are
called activities of daily living (ADLs). They are
what healthy people can carry out and are used
to assess the state of a patient’s independence and
health. The ADLs are listed in the box below.
Box 1.2 Activities of daily living
The activities of daily living (ADLs) include
Living processes
It is very hard to come up with a definition of
life, what it is and what distinguishes living
from non-living things. The distinction between
living and non-living things, by which we mean
things that have never been alive (your car, the
plate your food is on, for instance) as opposed
to dead things which used to be living, is a concept, an idea, that underpins much of what is
called natural philosophy, the branch of philosophy that all the sciences emerged from as subject areas about 2500 years ago. Biology is the
science that studies living organisms. Because
life itself is hard to define, biology defines living
organisms by what they do rather than what
they are.
Both living things and non-living things are
made of material substances, matter, which is
composed of atoms. In this respect what we are
made of hardly distinguishes us from non-living
things. In fact, the study of what we are made
of could be left to the same scientists who study
what everything is made of, chemists and physicists. What distinguishes the living from the nonliving is not therefore material substance, but
biological living processes – what organisms do.
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maintaining a safe environment,
working and playing,
growing and developing,
eating and drinking,
cleansing and dressing,
sleeping and
These are the activities that this book
will explore as they inform much of
health care and provide the link between
biology and health. The activities will
also be looked at as ones that maintain
and are maintained in homeostasis. The
changes that occur during changes in
lifestyle such as during physical activities or sleeping will be explored, as will
changes during lifespan from birth to
old age. They will all be put within the
context of the variables that affect them
and that they in turn affect.
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The link between our biology and our health
can be made even clearer if we think of homeostasis and ADLs (see box below).
Health Connection
Homeostasis and ADLs
Healthy, independent organisms maintain their own homeostasis, while those we think of
as having failing health cannot maintain their homeostasis and thus they cannot maintain
the cells of which they are made. When this maintenance is compromised we define an
organism as unhealthy or ill. If the organism cannot repair itself it may die. The alternative is that the organism becomes dependent on others, particularly those in health care
When we are in good health we don’t notice that we are, in fact, maintaining ourselves,
feeding ourselves, moving ourselves, communicating, breathing and all the other activities
of daily living (ADLs). We only tend to notice when things go wrong.
Homeostasis is used as a measure of health in biomedicine. If homeostasis fails it is a
measure of ill health and leads to clinical intervention.
In the biomedical model of health, diagnosing is the analysis of a problem and what
is causing it and is carried out to ascertain which part of us is not fully functioning and
maintaining itself. When that is done treatment is carried out to correct what is wrong.
This is the basis of clinical intervention and treatment so that we can return to being fully
homeostatic and functioning as healthy, independent people.
Health, homeostasis and independence are therefore linked in the biomedical model of
Losing the ability to carry out one of the ADLs may impact on one or many of the others.
For instance, losing the ability to move prevents or reduces the ability to fetch food or
water and therefore may lead to health problems such as malnutrition or dehydration.
The environment
There are two environments that affect living
the external environment – the universe in
which all life exists;
the internal environment – the body that
living things create and maintain.
The external environment
While we all wish for a safe environment, the
environment in which all living organisms exist,
the external environment of this planet Earth
or what we call nature, is indifferent to our survival. It is passive, and merely permissive of our
being here. For example, some compounds on
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this planet, such as lead and uranium, are quite
dangerous to us. Volcanic eruptions and earthquakes are evidence that this is not a benign
planet. However, as living organisms we adapt
to what is available on this planet to sustain our
lives and to thrive. We are made from the materials found on Earth, which appear originally to
have come from the ‘big bang’. The atoms we
are made of made something else before us and
will make something else when we are gone.
We are a sort of recycling system and you will
see in Chapter 9, ‘Eating and Drinking’, that we
eat other organisms or their products and then
eliminate what is waste for us but fodder for
another organism!
The external environment is not set or constant; it varies between places and fluctuates
at different times. Temperatures change, air
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composition changes, pressure changes, humidity changes and we must cope with all of these
changes and the alterations to all these variables
(things that can vary) if we are to survive and thrive.
For example:
Changes in the external environment may
affect our health.
Changes in the types of pollen from flowers
in the external environment may cause us
to have allergies.
Changes in air composition may cause breathing difficulties such as asthma. Changes in
pressure may not only make our ears ‘pop’
but may cause circulatory problems, as seen
in deep vein thrombosis (DVT).
Changes in external temperature affect our
body temperature; we become too hot or
too cold and need to adjust our temperature
to avoid damage to our cells which would
result in ill health.
our internal environment in the face of an
external environment which we cannot control and which varies constantly. Homeostasis
is thus central to biology and health.
While we cannot really control the external
environment to make it safe for our survival,
through physiological mechanisms described
in this book we try to make our own internal
environment safe for our survival, our health,
to maintain it within acceptable ranges.
Homeostasis and health: Linking
the external and internal
To understand how we maintain a stable internal environment we can look at the problem
in parts:
Chapter Reference
All these variables and how they are measured
are discussed further in Chapter 2, ‘Working
and Playing’ (see p. 35).
What internal environment are we trying to
Why are we trying to maintain it?
How do we maintain a constant or stable
internal environment?
What happens when we don’t maintain this
stable internal environment?
The internal environment
Wrapped around the outer edge of our bodies is a tissue so familiar that we forget that
it is a living entity – skin. It forms a barrier
between us and the external environment.
Everything contained within it is part of our
internal environment. This is composed of
many different chemical materials, discussed
in Chapter 2, ‘Working and Playing’. Some of
our inside environment is solid, some liquid
and some gas. All of it is adapted to be able to
carry out the functions of our bodies, which in
turn allow us to carry out the activities of daily
living. Disrupting the
physical or
internal environment affects our health. We
therefore invest a lot of effort in maintaining
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The internal environment that is
The internal environment operates around a
narrow range for each variable.
The variables (in bold below) that need to
be controlled around strict ranges include
the correct water balance – called osmosis –
for the movement of substances around the
the correct salt concentrations – also called
electrolytes or ions – for the correct movement of substances around the body and for
chemical processes to occur;
the correct acid and base levels – called
pH – for chemical processes to occur;
the correct sugar levels – for energy
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the correct nutrient levels – for growth and
the correct temperature levels – for chemical processes to work;
the correct chemical levels – for chemical
processes to work;
the correct oxygen levels – for energy to be
the correct carbon dioxide levels – for blood
gases to be maintained;
the correct protein levels – for growth and
the correct cell numbers – for body maintenance and development;
the correct size – for growth.
Health Connection
Changes in our internal
Changes in our internal environment can have drastic effects on
our health. For instance, changes
in the amount of blood in our body
due to blood loss can cause shock
and even death, while increases in
blood volume can cause high blood
pressure. This in turn affects all the
components of our body, the cells
and chemicals that make up our
body and their ability to function,
which in turn affects our health.
Why we try to maintain homeostasis
We need to maintain our internal environment; otherwise adverse effects can occur if we
become, for example, too
hot – proteins congeal;
cold – metabolism stops;
dry – blood transport stops;
wet – blood pressure is high and nutrients
are diluted;
acidic or alkaline (basic) – metabolic processes can’t occur;
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high or low in electrolytes – transport,
metabolic processes and nerve conduction
are affected.
All of these variables will be explained in subsequent chapters.
Homeostasis is a mechanism that maintains optimum internal conditions for cells and
therefore maintains our health.
How homeostasis is maintained
To maintain any system one needs to know what
is happening, if there are changes, and how to
alter the system in an ordered, measured way
to its optimal conditions. Homeostasis does all
of that to maintain a suitable internal environment by carrying out three general processes:
recording what is happening to each variable. There is no possibility of maintaining homeostasis unless it is known what
is to be maintained and if it has fluctuated
(changed) at all from where it should be;
collecting and monitoring this information
to coordinate a response. Any change that is
recorded needs to be collected into a central
area so that a coordinated response can be
made rather than an erratic, disorganised
response which could further endanger the
internal environment;
responding with an appropriate behaviour.
An appropriate response must be made to
the variable that has fluctuated rather than
randomly responding to change.
Step 1: Each variable is measured. This is done by
specific receptors, cellular devices that are tuned
to a particular condition, modality, and receive,
measure or detect any fluctuations from their set
point. For example, just as a room thermostat is
set to a particular temperature, so in the body
there are cellular receptors tuned to a particular temperature, 37°C. These temperature receptors, with their specialist functions, are called
thermoreceptors. Any fluctuation from 37°C is
noted and a signal sent to the monitoring area.
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Step 2: The monitoring and coordinating area for all the signals from the various
receptors is in the brain, in an area called
the hypothalamus. It is the control centre
for homeostasis. Many of the responses are
brought about by the autonomic nervous
system, although some involve the voluntary nervous system or the endocrine system.
Any changes detected by receptors are sent to
this area, which coordinates and controls an
appropriate response.
Chapter Reference
The endocrine and the nervous systems are
discussed in Chapter 4, ‘Communicating’ (see
p. 102).
Step 3: This control centre then sends signals
to the body to bring about the correct response
or effect. The response is brought about by an
effector, bringing a particular effect into being,
for example an increase or a decrease in temperature. This response must be brought about
by changes in the internal environment, heating ourselves up or cooling ourselves down, for
instance. There are various effectors depending
on the response required.
The receptor therefore measures the input
of a signal, the coordinating area takes all the
inputs and decides what output is needed and
then sends a signal to an effector which generates the appropriate response or output.
Box 1.3 General features of
homeostatic control
1. Receptors detect a change.
2. Control centre receives signals of a
3. Effectors change behaviour.
Receptors are constantly measuring the variable they are tuned to, such as temperature,
water levels or pH levels. These can change any
moment and receptors are good at detecting
9781403_945471_02_cha01.indd 7
change, rather than detecting a variable that
doesn’t vary (is constantly the same).
The control centre is constantly receiving
information from all the receptors about the
state of all the variables and constantly coordinating responses.
Health Connection
Homeostatic control centre
The control centre for homeostasis
is in the brain. Damage to the brain
can affect this area, and if so coordinated and appropriate responses can
be affected. This damage can come
about through many causes, such
as trauma to the brain, infections
and pathological (disease causing)
disorders. An uncoordinated or
inappropriate response would
affect homeostasis, and the internal
environment would be compromised. This is turn would affect all
the processes of the body.
The effectors are often trying to counterbalance a change. For example, if you are too
hot, the appropriate effector will try to make
you cooler. If you are too cold, the appropriate effector will try to make you warmer. The
effector is therefore working in the opposite
direction to the signal. This is an example of
negative feedback.
Negative feedback
Imagine you are standing upright. You sway to
the left, but your sense of balance brings you
back to the centre. You sway to the right, but
again your body brings you back to the centre.
This is the way that negative feedback works. It
doesn’t matter which direction the change is in,
too much or too little, it is opposed by the body,
which tries to bring it back to where it was,
in this case bringing you back to your centre.
Negative feedback is where changes are opposed.
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Temperature levels are also controlled in
this way. If you think of a room thermostat
set at 20°C, when the temperature of the room
decreases below 20°C the thermostat receives or
detects the information and sends it to a control
centre which sends information to the boiler to
carry out an effect, in this case to increase the
heat (turn on the heating). When the temperature increases to the set point the thermostat,
which, continues measuring the temperature
sends the information to the control centre,
which sends information to turn off the heating. In a human being if the temperature varies
too much from 37°C mechanisms are switched
on to restore the temperature (Figure 1.1).
becoming less dehydrated. Positive feedback
amplifies the situation, reinforcing the change
rather than opposing it.
For example: Would you use positive feedback for controlling temperature? What would
happen if you did? If you were hot you would
get hotter and if cold you would get colder. Not
very useful for these variables and homeostasis!
Positive feedback is used in a few control
mechanisms of the body when if a process
starts you don’t want to suddenly stop it; you
want it to continue until complete.
Both negative and positive feedback require
the same homeostatic mechanism: a detector, a
control centre and effectors.
Chapter Reference
Health Connection
Temperature regulation is discussed in
Chapter 5, ‘Controlling and Repairing’ (see
p. 142).
Positive feedback
Blood clotting and uterine contraction during labour are both under
positive feedback rather than under
negative feedback.
Once blood clotting starts it
proceeds (reinforces the change
direction) until the area is completed.
With uterine contraction again it
proceeds until the foetus is born. If
it was under negative feedback, as
the contraction started it would be
opposed and the foetus would not
be pushed out. Positive feedback
allows processes, once started,
to proceed to completion. It is
Positive feedback
Positive feedback leads to a greater departure
from the original level. It operates by measuring
the current state in your body of a variable, for
example water levels, and comparing it to the
desired level your body should be at. The difference between the two is the error. In positive feedback the error is increased. It reinforces change.
If you think about the swaying body again,
in positive feedback if you sway from the centre
to the right, positive feedback increases the sway
until you fall over – it reinforces the change. If
you sway to the left it reinforces that too until
you fall over to the left.
If you were dehydrated you would become
more dehydrated, rather than drinking and
Corrective response
Variable increase
No change in variable
Variable decrease
Negative feedback
9781403_945471_02_cha01.indd 8
Corrective response
We are also capable of feedforward,
which means anticipating our needs
or a potential disturbance to homeostasis. For example, when we eat
dry food we anticipate becoming
dehydrated so we drink at the same
time, before we actually become
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Negative and positive feedback and feedforward
all help to maintain homeostasis. They are also
all parts of actions we carry out to maintain
our internal environment – for example, drink
water, move to a warmer place, eat food. We
often do these actions without realising that
we are being prompted, motivated, to do so to
maintain our homeostasis. Homeostatic mechanisms have occurred internally, for example
monitoring water levels, releasing hormones to
alter thirst or to alter water absorption by the
kidneys, but what you notice is your motivation to behave in a certain way.
Chapter Reference
Motivation and hormones are discussed in
Chapter 4, ‘Communicating’ (see p. 102).
Water balance is discussed in Chapter 10,
‘Eliminating’ (see p. 282).
What happens when homeostasis
is not maintained?
If homeostasis is not maintained the body strays
too far away from the limits in which it can
survive and flourish. This threatens health and
can lead to death.
Ill health is when your body is not behaving homeostatically. It has been challenged
and cannot effect the appropriate change. We
can intervene clinically or medically at this
stage to restore the internal environment if
the patient cannot restore their own environment independently. In fact that is the main
purpose of medical intervention, restoring
Health Connection
Dehydration – water input and
Patients who have lost fluids need
the fluid to be replaced to avoid
dehydration. Much water is lost
from our bodies in urine. We can
measure the amount of fluid that
is lost in urine and we can measure
how much fluid a person has drunk
or replaced in their bodies. These
observations are made to avoid
the patient becoming dehydrated,
resulting in, among other conditions,
altered blood pressure.
Health Connection
Signs, symptoms and diagnosis
When we are ill and seek medical help we tend to present ourselves to the health professional with signs and symptoms of an illness. Signs are measurable and observable, such
as blood cell counts, temperature and skin rash. Symptoms are subjective reports by the
patient and are more general, such as pain, fever and nausea.
The health professional must then diagnose (work out) what these signs and symptoms
indicate (show) by
finding out which variable is outside the correct range (temperature, pH, etc.);
discovering, through appropriate investigations (such as blood pressure measurements, urine
sample chemical analysis), what is causing the system to malfunction;
deciding on the appropriate treatment to remove the cause of the problem or adjust the
body by clinical intervention so as to restore the homeostasis of the body.
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Box 1.4 Summary – Homeostasis
The environment in which we live is constantly fluctuating. We must maintain our own internal
environment, which is different from the external environment and can also fluctuate due to
changes in our daily activities.
To maintain our internal environment, to keep it suitable for us to survive, we have receptors.
Each receptor can measure a particular variable, such as temperature or water levels or blood
pressure. The measurement obtained must be sent to a control centre and the control centre
must decide what to do and send signals to effectors to effect a change in our behaviour to
maintain homeostasis.
Change can be brought about by
negative feedback, where the change in a variable is opposed;
positive feedback, where the change in a variable is reinforced (or increased);
feedforward, where there is anticipation of need.
Detailed mechanisms of homeostasis will be discussed in each ADL chapter.
Levels of organisation
The biology of life
To study how living organisms survive and
flourish, biology divides itself into separate levels of explanation based on size. We can start
from the lowest level and work up to the whole
organism (Figure 1.2):
Cells and organelles
atoms and elements,
At the lowest level, atoms, elements and molecules, some basic chemistry is needed to
understand why they are important in biology
and health and how they work in compounds
such as nutrients and drugs. We need to look at
what they are made of, the material, and how
they react, the energy. This will be discussed
in Chapter 2, ‘Working and Playing’. In this
chapter we will look at the organisation at the
biological level: cells, tissues and organs.
9781403_945471_02_cha01.indd 10
Cells are probably one of the hardest entities
to describe and to imagine. It is the cell that
defines life and is life. We are our cells. We
started out as one fertilised egg cell with material donated by our mother and our father in
a unique combination that makes us. This fertilised egg then went on to grow and divide,
taking in nutrients to grow and then divide
to make more and more cells. We humans
are composed of about 1013 cells – that is a 1
with 13 noughts after it, or 10 trillion. When
cells develop in the embryo they differentiate; that is, they become different from each
other. They alter shapes and functions to carry
out what is needed in the animal to which
they belong, in this case humans. Cells can
join together to form tissues and organs, all
the anatomical structures that carry out the
physiological functions to keep the individual
alive by keeping the cells that the individual is
made of alive.
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Atoms and
Cells and
(combinations of organs)
Levels of organisation
Chapter Reference
Development is discussed in Chapter 3,
‘Growing and Developing’ (see p. 64).
Cells are the basic functional units of life. They
are the smallest discrete functional units that
are able to be described as alive. Cells carry out
a number of chemical reactions, taking what
they need from their surroundings, food and
water for example, converting these into what
they need to carry out their living processes
9781403_945471_02_cha01.indd 11
and producing waste products which they must
excrete. These reactions are part of what are
called metabolic reactions and mean that the
cell is like a little chemical factory manufacturing all that it needs to maintain itself and its
surrounding cells and to maintain their internal conditions.
The chemicals making up a cell are large
organic molecules such as carbohydrates, fats,
proteins and nucleic acids. Cells obtain these
chemicals from food, so without food, which
contains those chemicals called nutrients, the
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cell cannot survive. Some of the chemicals from
food are used to replace worn-out parts of the
cell and some are converted to energy in the
form of another chemical called ATP. Energy
is used for transporting substances, chemicals,
into and out of the cell and for cell movement and metabolism, the processes needed to
keep the cell alive. All of the processes carried
out by a cell to keep itself alive are called cell
and to maintain itself through various metabolic processes. This takes energy, which cells
get from converting food such as sugars into a
chemical form of energy called ATP. The energy
is used for transport of substances into and out
of the cell (discussed below) and for the many
chemical reactions needed by the cell.
Chapter Reference
Energy and ATP are discussed in Chapter 2,
‘Working and Playing’ (see p. 35).
Chapter Reference
Chemicals, nutrients, energy and metabolism are discussed in Chapter 2, ‘Working and
Playing’ (see p. 35).
The structure of cells, their form, is part of their
anatomy. The processes that cells carry out,
their functions, are part of their physiology.
Health Connection
When the anatomy or physiology of
a cell alters from normal it can cause
an imbalance in homeostasis and
lead to disease. This is the area of
pathology – the study of disease. If
it is a physiological malfunction the
area of study is pathophysiology.
The structure of cells
Cells have an outer membrane which forms
a boundary and keeps the contents of the
cell in and most other things out. This membrane is permeable to water and fats, but not
to sugars and proteins, which must be actively
transported into the cell. Active transport is discussed below.
Inside a cell are various small organs, called
organelles, and other structures that help to
carry out the function of the cell. The main
purpose and function of a cell is to be alive
9781403_945471_02_cha01.indd 12
Organelles and structures inside the cell
The main organelles and other structures inside
the cell, their location and function are listed
The three main areas of a cell are
the cell membrane, which surrounds the
the nucleus, usually in the centre of the cell,
the cytoplasm, a watery–salty liquid inside
the cell where all the other main structures,
organelles, of the cell are found floating.
Health Connection
Cells can be taken from a patient (by
a procedure called a biopsy) to be
examined. As cells are very small and
not visible to the naked eye they can
be magnified under a microscope.
The cells are first stained with
various chemicals to highlight the
anatomical structures for viewing.
The study of cells in a clinical setting
is performed by histologists and is a
branch of pathology.
The cell membrane is also called the plasma
membrane. It is made of two layers of lipids
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(fats) which have a chemical phosphate group
attached, so the layers are also called a bi-layer
of phospholipid. There are proteins attached
to either the internal or external surface of
the membrane as well as proteins embedded
through the membrane. These proteins are
often involved with transport of substances
into and out of the cell. Proteins are discussed
below. Lipids are hydrophobic, disliking or
repelling water, while the phosphate molecules are hydrophilic, being attracted to water
(Figure 1.3).
Chapter Reference
Chemicals such as lipids and phosphates,
and proteins and their properties, such as
hydrophobicity, are discussed in Chapter 2,
‘Working and Playing’ (see p. 35).
The nucleus is a large structure within the
cell. It has its own membrane surrounding it,
the nuclear membrane, similar to the plasma
membrane of the cell. It is thus separated from
the rest of the cell. It contains long structures
called chromosomes containing a material
called DNA. This DNA is our genetic material,
with coding sequences called genes. Genes
Health Connection
Cells and ADLs
The cell is the unit from which all
the bigger organs and systems of
the body, such as the heart, the
liver and the blood, are made.
Keeping cells healthy is the basis of
homeostasis, maintaining the cell in
its optimum condition and environment. The adult body is made of ten
trillion cells, so keeping the body
healthy requires keeping all the cells
of the body in optimum conditions.
All the systems of the body and all
the ADLs are primed to do this.
contain the instructions for how to assemble proteins. Chromosomes are a mixture of
the genetic material and scaffolding materials
made of proteins and sugars that protect the
DNA and help it in its function. Also within
the nucleus is a large body called the nucleolus,
which also contains a form of genetic material used in making ribosomes – the structures
that make proteins from genetic material. The
nucleus thus contains this DNA, which is the
instruction material for assembling proteins.
lipid tails
lipid tails
phosphate molecules
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Lipids facing inside
of cell
Lipids facing outside
of cell
Cell membrane showing lipid phosphate bi-layer
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Most of the functions of the cells are carried out
by proteins. The instruction manual for assembling proteins, the genes, is very precious: if
they are damaged by being in the cytoplasm,
the instructions on how to make proteins are
lost. So genes are kept separate from the cytoplasm area, where all the metabolism of the
cell, its survival, is happening. Keeping it separate from the rest of the cell inside a nucleus is
a way of protecting the genetic material.
Not only does the genetic material tell the
cell how to make proteins, but it tells future cells
how to make proteins. It is part of the generation of new cells; hence the words genes, genetics and generation all have the same root.
Chapter Reference
Genes, genetics, DNA and protein assembly
are discussed in Chapter 3, ‘Growing and
Developing’ (see p. 64).
Within the cell are a number of specialised
structures – organelles. Each of these carries out
a particular specialised function or activity. The
nucleus is one such organelle. Below are examples of others.
Health Connection
Genes and proteins
The genes are the instructions for
how to assemble proteins. Any
damage to the genes compromises
our ability to make proteins (it is
called a mutation). To avoid damage
the genes are kept separately from
the rest of the cell behind an extra
layer of protective membrane, the
nucleus. Damage can still occur from
the external environment, such as
ultraviolet (UV) rays of sunlight, or
by the ingestion of toxic chemicals,
the lack of essential nutrients or
extreme temperatures.
9781403_945471_02_cha01.indd 14
Ribosomes are structures in the cytoplasm but
are not strictly organelles, as they are not bound
by a membrane, which other organelles are.
They are the site where proteins are manufactured. This illustrates how the various functions
inside cells are compartmentalised to different
areas and organelles, each with its own specialist function. The nucleus holds the instructions
for how to assemble proteins, but the ribosomes
are the actual place of manufacture and assembly, the factory floor. If the ribosomes make a
mistake in assembling a protein, there will be
one bad protein, but the next one will follow
the genetic instructions. Ribosomes may be free
inside the cytoplasm, but are usually attached
to endoplasmic reticulum, discussed below.
The cytoplasm is a watery fluid in which
organelles and other structures exist within the
cell. The fluid is composed of water and salts
(electrolytes). The organelles carry out various
functions and the cytoplasm is a favourable
environment for these functions (Figure 1.4).
The cytoskeleton is a fine network of proteins that supports and gives shape to the cell.
Mitochondria are organelles involved in producing energy for the cell; they are often referred
to as the ‘powerhouse of the cell’. They oxidise
glucose into ATP molecules. They contain their
own genetic material.
Health Connection
Mitochondrial diseases
Since mitochondria have their
own genetic material they can
have mutations that are unique to
mitochondrial genes. Many metabolic
disorders are linked to mutations in
mitochondrial DNA.
We inherit our mitochondrial
genetic material solely from our
mothers. Forensic and anthropological scientists can use this to
trace us back to our foremothers.
This can also help in establishing
mitochondrial disorders that might
be inherited and cause disease.
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Rough endoplasmic
Golgi apparatus
Smooth endoplasmic
Bi-layer of plasma
FIGURE 1.4 A generalised diagram of a cell showing the cell membrane, cytoplasm and
organelles, including the nucleus and mitochondria
The Golgi apparatus is a stack of flat sacs of
substances like the plasma membrane. These
sacs are involved in packaging substances inside
the cell and transporting them around the cell
in vesicles, small sac-like bubbles of membrane
in the cytoplasm, either for use by the cell or to
be released from the cell.
The endoplasmic reticulum comes in two
kinds, smooth and rough.
The smooth endoplasmic reticulum is a
series of tubes which makes cholesterol, a steroidbased substance found in membranes and other
steroid-based substances, such as some hormones,
and which is involved in detoxifying drugs.
The rough endoplasmic reticulum has
ribosomes attached to the tubes and allows
transport of proteins around the cell.
Lysosomes are vesicles which contain
enzymes that digest worn-out parts of cells and
foreign substance that have invaded the cell,
such as bacteria.
Some cells have microvilli projecting from
the external side of the cell membrane. These
increase the surface area of the cell, the amount
of the cell on the edge or surface rather than
deep within the cell. Increased surface areas
allow for easy cell transport, discussed below.
9781403_945471_02_cha01.indd 15
They are particularly found on cells in the small
intestine of the gastrointestinal tract.
Some cells have extensions from their cell
surface that are involved in moving the cell
along or moving substances along the outside
of the cell. These cilia are found on cells such
as follicles and ovary cells and in the respiratory
system, discussed in Chapter 7, ‘Breathing’.
Health Connection
Cells and death
All the organelles of the cell have
particular functions. If they fail
in their function the viability and
health of the cell is compromised
and it may die. Cells that are failing
are encouraged to die by a process
called apoptosis so that poorly
performing cells do not continue
to use up the resources of the body
and potentially harm the other cells
of the body. If too many cells are
poorly performing our health is at
risk. If too many cells die our life is
at risk.
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Cell sizes, shapes and lifespans
Cells come in different shapes, sizes and
lifespans. Red blood cells, for example, are very
small and have a particular shape, a biconcave
disc, which allows them to squeeze through
narrow blood tubes called capillaries. They
have lost their nucleus during development.
The nucleus is where genetic material is stored.
The genetic material is the instruction manual
of how to make proteins. The main protein in
red blood cells is haemoglobin, a protein that
carries oxygen from the lungs to all the cells
of the body. Red blood cells are full of haemoglobin. However, if the haemoglobin proteins
become worn out and need replacing, the red
blood cell does not have the instruction manual of genetic material to tell it how to do so.
So the red blood cell gradually decays and dies.
New red blood cells are constantly being made
to replace dead ones.
This illustrates a few things about cells:
Cell shape
Although we tend to show a cell as a generic
round cell, cells come in different shapes to suit
the function they carry out. In biology a lot of
Health Connection
Haemolytic anaemia
Changes in shape can affect the ability
of a cell to carry out its role (function).
Red blood cells are usually biconcave
discs, but in one particular disease,
spherocytosis, the red blood cell
takes on the shape of a sphere (hence
the name of the disease). Because of
this change of shape the cell’s ability
to carry out its function (the transport
of oxygen) is severely compromised,
which results in a condition called
haemolytic anaemia. This will be
discussed further in Chapter 7,
9781403_945471_02_cha01.indd 16
emphasis is put on the relation between the
structure of something and its function, a bit
like good design. Structure falls under the category of anatomy and function falls under the
category of physiology (Figure 1.5).
Cell size
Cells have different sizes, also an anatomical
feature, to suit their function. For example, the
size of the female gamete, the unfertilised egg,
and the size of the male gamete, the sperm,
are very different. This is due to their different
roles. Bird eggs are much bigger than human
eggs. This is because bird eggs are laid externally from the mother. The embryo must grow
inside the shell with no other nutrients being
supplied during the embryo’s maturation,
merely warmth from the parent during incubation. Humans are mammals and grow via a
placenta linking the mother’s nutrient supply
to that of the embryo, providing continuous
nourishment. Not all the necessary nutrients
therefore have to be included at fertilisation.
With normal cells of the body there is also a
range of size reflecting the function of the cell.
Red blood cells are very small and liver cells are
very large, reflecting their different functions.
Red blood cells have one function, carrying
oxygen. Liver cells carry out many metabolic
It is useful to think about sizes in order to
understand what cells look like and how complex they are, containing all the subcellular
organelles within them (see Table 1.1).
Cell lifespan
Cells have different lifespans. Red blood cells live
some 120 days. Brain cell neurons live throughout your life. Liver cells are replaced as needed.
You can have a large part of your liver removed
and it will grow back. Blood cells are also constantly replaced. Scientists would like to know
the mechanism for getting cells to re-grow, part
of the remit of stem cell and regenerative medical research, so that we could re-grow damaged
brains and hearts.
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Box 1.5 Sizes of human beings
Humans tend to be measured in the standard unit of metres. The average human is about
1.8 metres (1.8 m), or just under 2 metres.
1 metre is made up of 100 centimetres (‘centi’ is the Latin prefix for 100).
1 metre can also be described as being 1000 millimetres. In other words a centimetre has
10 millimetres in it.
To visualise this look at a 1 m ruler marked with 100 centimetres, each composed of 10
If a human is 1.8 m tall they are 180 centimetres (180 cm) or 1800 millimetres (1800 mm).
Even though humans are about 1.8 m tall, inside of them are many metres of intestines and
hundreds of metres of DNA.
Cells are microscopic because they cannot be seen with the naked eye and must be magnified by a microscope. They tend to be a millionth of a metre long, or a thousandth of a
Table 1.1 Some measurement sizes for comparison
1 m (= 1 metre, which is 1000 millimetres or 100 centimetres)
3 metres, length of a nerve cell of a giraffe’s neck
1.8 metres, average height of a human
1 mm (= 1 millimetre, which is a 1/1000th of a metre or 1/10th of a cm)
120 mm, diameter of an ostrich egg (a dinosaur egg was much larger)
1 μm (= 1 micrometre, which is a millionth of a metre or 1/1000th of a millimetre)
100 μm, human egg
90 μm, amoeba
10–100 μm, most plant cells
10–30 μm, most animal cells
9 μm, human red blood cell
3–10 μm, the nucleus
3 μm, mitochondrion
2 μm, E.coli – a bacterium
1 μm, diameter of human nerve cell process
1 nm (nanometre, 1 nm = 1/1000th of a micrometre)
200–500 nm, organelles such as lysosomes
150–250 nm, small bacteria such as Mycoplasma
100 nm, large virus
11 nm, ribosome
10 nm, thickness of cell membranes
2 nm, diameter of a DNA alpha helix
0.8 nm, amino acid
0.1 nm, diameter of a hydrogen atom
9781403_945471_02_cha01.indd 17
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Transport into and out
of the cell
I Epithelial tissue
Simple epithelia
Columnar epithelia
II Connective tissue
Fat cells
Blood cells
III Muscle tissue
lV Nervous tissue
There are millions of different organisms on this planet. Humans represent just one type. Organisms such as
amoebas and bacteria are made of a
single cell. They are called unicellular
organisms. All of their functions of
life, growth and death are carried out
in that one cell.
We humans are made of millions
and millions of cells; we are multicellular. All of these cells have gone
through a process called differentiation where during development different types of cells have developed
into shapes suitable for carrying
out the various functions needed to
keep the whole multicellular animal,
us, alive. Some cells become liver,
some heart, some bone, for example. All of them look different from
one type to another and do different
things – processes. But all of these
cells, whether from unicellular organisms or multicellular organisms, need
to keep themselves alive and that
requires replacing worn-out parts and
obtaining energy. All of these functions of each cell are called cellular
metabolism. Every cell needs to do
this to maintain itself. It is part of
what is called the housekeeping of
the cell, apart from its specialist functions to do with the particular type
of cell it has become during differentiation. Housekeeping and cellular
metabolism require getting chemical substances such as carbohydrates
and proteins and oxygen to each and
every cell. Once at the cell these substances then have to cross the plasma
membrane into the cell. Waste products and other substances have to be
removed from the cell. At the membrane there is, therefore, traffic of
FIGURE 1.5 A variety of cell shapes suited to the functions
which they carry out
9781403_945471_02_cha01.indd 18
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Health Connection
Chemotherapy is used in cancer
treatments to kill growing cancer
cells, but it also can kill any growing
cells. Normal cells that are growing
and dividing would be affected
by chemotherapy, such as blood
and skin in other words those cells
with shorter lifespans which are
constantly being replaced are most
across cell membranes; the maxim is ‘Like dissolves in like.’ However, non-fats need to be
transported into and out of the cell across the
plasma membrane. There therefore need to be
transport mechanisms for doing this.
There are various ways of moving substances
across the cell membrane. Below are three main
Box 1.6 Summary – Cells
Cells are microscopic entities.
They have an outer boundary – a
They contain a watery fluid – cytoplasm.
In the cytoplasm float organelles.
Organelles carry out specialised functions (activities).
Cells can only survive in a limited
range of conditions.
If the condition varies too much the
cell will die.
If too many cells die, we die.
Homeostasis attempts to keep the
internal environment suitable for
cellular activity and survival.
Cellular activity alters the internal
environment and is discussed in later
substances into and out of the cell. This is called
cell transport.
Different substances have different ways
of crossing the membrane, the lipid bi-layer.
As the bi-layer is made of a fat-like substance,
other fats are more able to cross the bi-layer
than are non-fats. For example, oils and vinegars (a non-fat) are hard to mix in a sauce called
‘vinaigrette’, which is a salad dressing. Likewise
fats and non-fats are hard to mix in cells and
9781403_945471_02_cha01.indd 19
Diffusion (or passive diffusion) moves
substances down a concentration gradient
from high to low.
Active transport (and all active systems)
requires energy to move substances against
a concentration gradient.
Osmosis is the movement (diffusion) of
It is one of the rules of the universe that physicists have observed that substances tend to go
from areas of high concentration to areas of
low concentration. They do this without any
help. This has to do with increasing disorder
and is called entropy. It forms the basis of one
of the laws of thermodynamics and links living things with the energies of matter found
throughout the cosmos.
Imagine a vacuum flask, a flask with nothing
in it, not even air, into which you allow some
blue gas. The gas will diffuse into the whole
flask, not collect all together at the entrance.
It will go from an area of high concentration,
where you let it into the flask, to an area of low
concentration until it has diffused throughout
the flask and the blue molecules of the gas are
evenly spread out.
The problem is getting substances to go
from low concentration to high concentration,
which is sometimes needed in living organisms.
This requires energy to move the substances
against their natural tendency. This energy is
obtained from cellular metabolism, and this
mode of transport that takes energy is called
active transport.
In Figure 1.6 there is little of the substance
oxygen (O2) inside the cell and more of it
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outside. The O2 therefore moves down its concentration gradient from high outside to low
inside until it is the same on each side (called
The other substance, carbon dioxide (CO2),
would move in the opposite direction down its
concentration gradient from high concentration inside the cell towards the low concentration outside the cell.
Diffusion of substance
Diffusion into a cell
Diffusion out of a cell
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Facilitated diffusion
Facilitated diffusion is a form of passive diffusion, but it differs in that this diffusion is
mediated (helped) by proteins embedded in the
plasma membrane. These proteins either
allow the substance to move through specific
pores in the membrane (channels) or
bind the substance that is to diffuse across a
membrane to transport or carrier molecules,
which bind to the substance on one side of the
membrane and release it on the other side.
Both of these methods facilitate the diffusion.
Active transport
Active transport is transport that requires energy to
move a substance. It describes moving substances
against their concentration gradient, moving
them from low concentration to high concentration, rather than the other way by diffusion.
Most substances, whether moving by diffusion or by active transport, cross the membrane
at specific places where proteins or channels
exist for them. The movement is often very
specific, a protein in the membrane only
binding or transporting one type of chemical
(Figure 1.7).
Engulfment is where the membrane of the cell
surrounds particles to form a vesicle. This vesicle is a small sac formed by budding off from an
existing membrane. The substance inside the
vesicle is then transported either within the cell
or across the cell membrane.
Vesicles can
transport substances from one structure to
another within cells;
take substances from the fluid outside the
cell (extracellular fluid) – endocytosis;
release substances into extracellular fluid –
exocytosis (see Figure 1.8).
Cell membrane
Cell membrane
Facilitated passive diffusion
Passive diffusion
Cell membrane
Active transport:
Substance pumped
against concentration gradient
9781403_945471_02_cha01.indd 21
Passive, facilitated and active transport compared
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Endocytosis (taking in) and exocytosis (eliminating)
Health Connection
Pharmacology is the study of
medicines. Most medicines that
act on cells must be transported
into cells by diffusion, facilitated
diffusion, active transport or engulfment to have an effect on the cell.
How drugs get into cells is part of
the study of pharmacology.
Water, osmosis and body fluids
Water is the major fluid in the body. It forms part
of the transport medium, blood, and the medium
in which substances such as nutrients can dissolve in and around cells. It is a very good solvent,
allowing many solutes, particularly hydrophilic
(water loving) solutes, to be carried or dissolved.
Keeping the correct hydration levels is very
important for bodily functions. Too little water
and blood pressure drops due to lack of blood volume. Too much liquid and blood pressure rises
due to too much blood volume. The kidneys help
9781403_945471_02_cha01.indd 22
to control the levels of water in the body and this
is another example of homeostasis.
Chapter Reference
Water levels are discussed in Chapter 9, ‘Eating
and Drinking’ (see p. 241) and in Chapter 10,
‘Elimination’ (see p. 282).
Blood pressure is discussed in Chapter 7,
‘Breathing’ (see p. 184).
The movement of water into and out of cells is
called osmosis. Water moves, by osmosis, from
areas of high solvent (water) concentration to
areas of low solvent concentration. In other
words, water moves from areas with lots of water
and few solutes to areas with little water and lots
of solutes. Water thus moves down its concentration gradient. Osmosis is a kind of diffusion.
The effect of water movement on other substances, though, is to change them from being
diffuse to concentrated and those that were
concentrated become diffuse.
The fluids in the body can be found in various compartments:
intracellular, i.e. inside the cell;
3/12/2012 10:32:07 PM
extracellular, i.e. outside cells, such as blood,
plasma, lymph, cerebrospinal fluid;
intercellular or interstitial, i.e. between cells.
Health Connection
Replacing water
When replacing fluids that are lost
by a patient either we can give
water to drink or by infusion (into a
vein) we can deliver saline (a water
and salt solution at a strict osmotic
balance to match that of the plasma
of the blood). Water that is drunk is
usually a mix of water and salts at
a low concentration and is rapidly
mixed with the contents of the
stomach into a solution containing
other substances. We cannot infuse
pure water into a vein as this would
alter the osmotic pressure of the
surrounding cells, causing them to
swell and burst.
All cells of the body are in contact with extracellular fluid, from which they obtain the
chemicals they need. We operate all our reactions in a watery fluid both inside and outside
of our cells. Any chemicals (gases, nutrients
from food) that we bring into our bodies from
the external environment must therefore be
moistened to be suitable for our cells.
Health Connection
Water and health
Water and hydration are vital for
human life. Dehydration is a major
problem in many environments,
particularly hospital settings and
when patients cannot re-hydrate
themselves. Hydration is discussed
further in Chapter 9, ‘Eating and
Drinking’ and in Chapter 10,
In Figure 1.9 salt is at a high concentration and
water is at a low concentration on the right,
while water is at a high concentration and salt
at a low concentration on the left. Water will
diffuse from high concentration on the left to
low concentration on the right by osmosis until
both sides have similar concentrations of salt
and water; they are then said to be in equilibrium. This is a dynamic state where the number
of salt atoms or water molecules moving from
To achieve
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left to right is equivalent to the number moving
right to left. This is a very important concept
in biology, chemistry, physics and therefore in
health. In health we are in dynamic equilibrium
with our environment. In ill health we are not.
These in turn can be part of even larger structures called organs.
Chapter Reference
Development and differentiation are discussed
in Chapter 3, ‘Growing and Developing’ (see
p. 64).
In the above sections a cell has been described.
Organisms composed of one cell are unicellular.
Organisms composed of more than one cell are
multicellular. Humans are multicellular organisms. The cells of our bodies come together to
form large structures that carry out the functions (physiology) of our bodies. These functions are to keep the individual cells of the large
organism, us, alive.
The cells we have talked about so far have
been generalised cells. Our bodies are made of
many cells and many different types of cells.
During development, cells differentiate into
different types of cells. Differentiated cells join
together to make large structures called tissues.
Each of the cell types in Table 1.2 has the features described for the general cell – a membrane, cytoplasm and organelles. Each of the
cell types differs from other cell types by the
shape of the cell or the inclusion of extra
organelles or the exclusion of organelles or
specialised proteins. These specialised cells can
then form groups of specialised cells called tissues, which can in turn carry out specialised
functions such as covering the body (epithelia)
or transporting substances (blood). The cells in
the group can be held together tightly, as in epithelia, or loosely, as in fat, cartilage, bone and
blood. They can have other characteristics that
group them together such as being contractile
(muscle) or conducting electricity (neurons).
Box 1.7 Summary – Cells and transport
Living organisms are made of cells, either unicellular organisms, such as bacteria and
amoebas, or multicellular organisms, such as plants, dogs and humans.
Cells are the structural and functional unit.
In biological organisms structure and function are closely linked.
The shape, size and lifespan of cells are also linked to what their functions are.
Cells are composed of various subcellular structures, organelles, which are themselves made
of various chemicals, such as fats and proteins.
The various structures inside a cell, the organelles, carry out the functions of the cell.
All of the organelles and transport methods of cells are used to maintain the cells’ metabolism – the functions cells carry out to keep themselves alive.
Different cells have different lifespans.
If a cell from certain areas of the body dies it can be replaced, but others cannot. If many cells die
all at once, the functions of the entire organisms may be compromised and death may occur.
To maintain themselves cells must transport substances into and out of themselves, to
replace worn-out parts and make energy, which is constantly being used up.
Substances cross the cell’s plasma membrane in various ways depending on solubility and
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Table 1.2 Cell types, locations and functions
Cell group
Epithelial cells
Barriers, absorption,
Tightly bound between
Linings of organs such as
digestive tract, skin
Epithelial – hormone
producing cells
Cell communication
(indirect via blood)
Secrete chemical messages
Thyroid, adrenal, pituitary
Connective – support cells
Maintain body structure
Produce specialised
extracellular material such
as elastin
Bone, cartilage
Connective – adipose cells
Physical protection, heat
Most of cell volume is fat
Under skin, around organs
Connective – blood cells
Transport oxygen,
Haemoglobin protein in
red blood cells carries
oxygen; immunoglobulins
label foreign particles
Red and white blood cells
Muscle cells
Skeletal muscle, heart
muscle, smooth muscle
Neuron cells
Cell communication
(direct, cell to cell)
Electrical potential
Germ cells
Haploid chromosome
Egg, sperm
To simplify categorisations, the cells that
form the adult can be grouped together into four
types of tissues based on their anatomy (what
they look like) and their physiology (what they
do). These four types of tissues are
epithelial – tissues that make linings and
tight junctions between cells, such as lining
the digestive tract or forming the outer layer
of skin;
connective – tissue that makes support and
transport structures with loose junctions
and matrix material in between the cells.
They can be solid or fluid such as bone,
tendons and blood;
muscle – tissue that can be made to contract,
such as cardiac, smooth, voluntary;
nervous – tissue that can conduct an electric
impulse or support tissues that are electrical
such as neurons and glia.
Each of these four types of tissues has further
Epithelial tissues are subdivided according to
whether there is a single layer of cells (simple) or
multiple layers of cells (squamous) and whether
the shape of the cells is cuboidal, columnar or a
9781403_945471_02_cha01.indd 25
mix (transitional). Different subdivisions occur
in different areas of the body so that the appropriate anatomical type is matched to the physiological need. For instance, areas that need to
protect the body, such as the skin, are stratified
to contain many layers so that damage to the
outer layers that are in contact with the outside
environment does not affect the inner layers
that are in contact with the internal environment of the body; areas that need to absorb
oxygen, such as in blood capillary vessels, are
formed from just one layer (simple). Areas that
secrete enzymes, such as in the digestive tract,
are also composed of one layer of epithelium
(simple) while areas that need to absorb nutrients from the digestive tract and transport them
to the blood are also simple, but need to have
additional surface areas called villi to allow for
fast absorption. The shape (anatomy) of a tissue
reflects its function (physiology).
Connective tissue cells are subdivided
into bone, cartilage, blood, dense and loosely
packed cells. These too reflect their function.
Bone is hard, giving rigidity and protection to
the soft underlying organs of the body. Blood
is composed of loosely packed cells in a liquid
3/12/2012 10:32:08 PM
that allows the tissue to move around the body
as a transport medium.
Muscle tissue cells are subdivided into skeletal
or voluntary (attached to and moving the skeleton), cardiac (in the heart pumping blood) and
smooth or involuntary (in organs moving substances such as food through the digestive tract).
All muscle cells can contract and relax in response
to electrical stimulation from nervous tissues.
Nervous tissue cells are subdivided into those
that carry information, neurons, and those that
support neurons, glial cells. Neurons carry electrical signals while glia provide a skeleton-type
structure for neurons and move nutrients and
waste to and from the neurons.
Health Connection
Tissues and cancers
Different cancers are categorised
by the tissue from which they
originate. The commonest cancers
also describe their tissue of origin;
carcinomas are from epithelial
tissues and sarcomas are from
connective tissues.
Collections of cells form tissues and tissues
can then be formed into organs. An organ is a
collection of specialised tissues that performs
a specific function, such as skin providing a
boundary around the body, kidneys filtering
and excreting waste products from blood, lungs
bringing air in from the external environment
to the internal environment and the heart
pumping blood around the body.
Chapter Reference
tissue that contracts to pump (or squeeze) blood
through tubes and an inner layer of epithelial
tissue that holds the liquid blood.
Some organs are composed mainly of two tissue types, such as skin, which has an outer epithelial layer and an inner connective layer. There
are other types of organs called membranes (not
the plasma membrane of a cell) which are also
formed of two tissue types, discussed below.
Very few organs are composed of one tissue type. One such organ is called a gland. It
is composed of epithelial tissue cells. Epithelial
tissues can form linings or barriers and absorb
or secrete. Glands are organs that secrete substances and epithelial cells are used in areas of
the body where secretion takes place, such as
in the gastrointestinal tract (passageway) or the
urinary tract.
As mentioned above, most organs of the body
are formed from various types of tissue. Glands
are formed from just one type groups of epithelial cells which produce specialised secretions.
There are two types of glands, exocrine and
endocrine (Figure 1.10), both secreting substances, but into different areas:
Exocrine glands have ducts secreting fluids
and chemicals into body cavities.
Endocrine glands release chemical secretions called hormones into the blood.
Box 1.8 Summary – Tissues
While there are many different types of
cells in the body they are categorised
into four tissue types:
Each organ and its role in an activity of daily
living are discussed in the chapters of this
Organs are usually composed of more than one
tissue type. For example, the heart has an outer
covering of connective tissue that holds it in
the chest (thorax), a middle layer of muscle
9781403_945471_02_cha01.indd 26
Epithelial tissue cells make watertight
Connective tissue cells support and
Muscle tissue cells move and pump.
Nervous tissue cells transmit information.
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Epithelial cells
from mechanical and chemical damage and
traps foreign particles. Mucous membranes are
found at all cavities that open to the exterior.
Mucosae are found in the
Secretory product
(into lumen)
Chapter Reference
Exocrine gland. This is formed of simple epithelial tissue which allows easy diffusion
of a substance out from (secretion) the cells
Mucous membranes are mentioned again
in chapters referring to the activity in which
they play a part. For instance, the mucous
membrane involved in digestion is discussed in
Chapter 9, ‘Eating and Drinking’ (see p. 241).
Mucous membranes
These are also called mucosae. They are moist
membranes. Mucosae consist of epithelial cells
and their secretions. The secretions are called
mucus. Mucus accumulates in the epithelial
cells, which swell full. The cell empties its contents to the free surface. The filled epithelial
cell looks like a goblet and is known as a goblet
cell. The mucus functions to protect surfaces
9781403_945471_02_cha01.indd 27
respiratory tract – see Chapter 7, ‘Breathing’;
gastrointestinal tract – see Chapter 9, ‘Eating
and Drinking’;
genitourinary tract – see Chapter 10, ‘Eliminating’.
Mucous membranes can also be adapted for
absorption – the taking in of substances – or
secretion of substances such as mucus.
The membranes discussed below are not the
plasma membrane of a cell, but a membrane
that surrounds tissues and organs. These membranes are thin, sheet-like structures covering
and protecting body surfaces, lining body cavities and covering the inner surface of hollow
organs such as the gastrointestinal (GI) tract
(the digestive tract along which food passes as
it is broken down) and the respiratory passage,
where air travels from the outside in.
These membranes are formed by sheets of
epithelial tissue and their supporting connective tissue. They are very similar to, and include,
skin. Their function is to cover or line internal
structure or cavities or to protect surfaces.
There are three main types of membrane
(Figure 1.11).
Serous membranes
These membranes are also called serosa. The
serosa secretes a watery fluid called serous fluid.
The serosa forms a double layer of cells of loose
areolar connective tissue lined by simple squamous epithelial tissue. These two layers form
a parietal layer – lines cavities;
a visceral layer – surrounds organs.
The layers are separated by serous fluid. Serous
fluid is secreted by epithelial cells and allows
the two layers to glide across each other. The
serous membrane thus prevents friction.
Serous membranes line cavities that do not
open to the exterior and are found in
plueral thoracic cavity and lungs;
pericardium – pericardial cavity and heart;
peritoneum – abdominal cavity and organs.
Chapter Reference
Serous membranes again appear in other
chapters. For example, serous membranes
surrounding the thoracic cavity are discussed
in Chapter 7, ‘Breathing’ (see p. 184).
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Synovial membranes are a type of serous
membrane found lining joint cavities and surrounding tendons.
They secrete synovial fluid as a lubricant,
as is often found around joints and cartilage of
the skeleton.
Cutaneous membrane
This membrane forms the integumentary system, which contains the skin and accessory tissue such as hair and nails. This is formed of an
outer epithelial layer and an inner connective
Serous fluid
Mucous membranes
line cavities that
open to the exterior
Serous membranes
line cavities that do not
open to the exterior
Synovial membrane –
a type of serous
membrane found
around joints
9781403_945471_02_cha01.indd 28
Body membranes: mucous, serous and synovial
3/12/2012 10:32:08 PM
tissue layer. The outer layer is mainly dry, with
a large amount of keratin protein in the cells.
The skin and nails help to form a protective
barrier between the internal and external environments and play a part in controlling body
temperature and maintaining a safe environment by excluding invading foreign organisms
such as bacteria and viruses.
Chapter Reference
The skin is discussed further in Chapter 5,
‘Controlling and Repairing’ (see p. 142) and
Chapter 3, ‘Growing and Developing’ (see
p. 64). Avoiding infection is discussed further
in Chapter 11, ‘Cleansing and Dressing’ (see
p. 299).
Repair of tissues
liable to damage and will be replaced again by
Some tissues are more able to regenerate
after damage than other tissues. Some tissues
cannot regenerate similar cells and replace lost
cells with scar tissue, which is formed from
fibrous connective tissue. This scar tissue cannot carry out the normal function of the appropriate tissue and the function of the tissue is
therefore compromised.
Tissues that regenerate easily:
epithelial tissue and
fibrous connective tissue.
Tissues that regenerate poorly:
skeletal muscles.
Tissues that regenerate mainly with scar tissue:
As with other homeostatic mechanisms of the
body, the number of cells we have in a tissue is
regulated by the number we need. If cells are
damaged they are replaced during a process
called tissue repair or wound healing. During
tissue repair cells are regenerated, i.e. generated
again, by cell division from a pool of cells called
stem cells. These are cells that are long living
in the body, but provide daughter cells that
are short living. The daughter cells have more
specialised functions appropriate to the tissue
in which they occur. For instance, damage to
epithelial cells will cause epithelial stem cells to
make daughter cells that will replace the damaged cells. These daughter cells will in turn be
cardiac muscle and
nervous tissue.
Chapter Reference
Tissue repair is discussed further in Chapter 3,
‘Growing and Developing’ (see p. 64) and
Chapter 5, ‘Controlling and Repairing’ (see
p. 142).
Organs and systems
Cells do not operate independently; they
operate in groups, tissues, which in turn form
organs. Organs operate to maintain the physiology of our bodies; our living processes need
Health Connection
The tissues that can repair easily, epithelial and connective, are also the tissues that are most
prone to cancerous growths. Epithelial tissue forms carcinomas, while connective tissues
form sarcoma-type cancers. Each time a cell divides to form new cells there are chances that
the copying of the genetic material, DNA, could be inaccurate and cause a mutation. This
in turn could cause abnormal growth, a characteristic of cancers. Common cancers are in
tissue that has a higher turnover of cells due to cells wearing out and being replaced by new
cells. This will be discussed further in Chapter 3, ‘Growing and Developing’.
9781403_945471_02_cha01.indd 29
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to maintain our internal environment and keep
our cells functioning.
Organs are fairly discrete structures both anatomically and physiologically. Some organs are
composed of only one type of tissue; for example,
glands are composed of epithelial tissue. Some
organs are composed of two types of tissue; for
example, skin is composed of epithelial and connective tissue. Most organs are composed of a
number of tissues; for example, the heart has an
inner epithelial layer lining the tubes and cavities,
a middle layer of muscle tissue that carries out the
pumping mechanism and an outer layer of connective tissue anchoring the heart to the chest wall.
Organs can in turn be part of organ systems (body systems) where two or more
organs work together to carry out a function;
for example, the stomach, intestines and
pancreas work together to digest food. These
systems work together to carry out the living
processes of the body, for example to digest
food into nutrients, to transport those nutrients to cells for metabolic processes and to
remove waste.
These systems then work together to form
the whole person.
Each of these organs and systems is discussed
in chapters throughout this book (see Table 1.3).
Table 1.3 Organs and systems
Organs and cells
Gonads (ovaries, testes), genitals (vagina, penis), uterus, placenta
Endocrine glands (pituitary, pancreas, adrenal, gonad)
Brain, spinal cord, nerves, neurons, glia
Skin, hair, nails, sense receptors, sweat glands, oil glands
Bone, joints
Muscles, tendons
Lungs, nose, trachea, bronchioles, diaphragm
Transport (circulatory)
Blood, lymph, heart, vessels
Mouth, teeth, stomach, intestine, liver, pancreas
Excretory (elimination)
Renal, kidneys, bladder
Immune (lymphatic)
White blood cells, thymus, spleen, nodes, tonsils
Health Connection
A community of cells
We have started with cells, progressed to tissues and now are looking at the organs and
body systems. It is hard to think down to the cellular and fluid levels to see that most of
what affects a large organ or system starts at a small cellular level, a cell not having what it
needs and therefore not acting in the normal physiological manner, which then affects the
cells around it, which then affects the whole person. We may be multicellular, but we are
really a community of cells each affecting and being affected by the other cells.
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Health Connection
Health and illness
When a patient presents with a problem it is often associated with an organ and therefore
has an effect on a whole system, which affects the whole body and person, making them
‘feel ill’ in general.
During health our bodies work as a cohesive whole. If cells start to malfunction they
can affect the organ in which they are, which in turn affects entire body systems and can
result in illness. Cells act independently, but exist in cooperation to maintain homeostasis
in health. Any malfunctions can therefore affect our health. The functioning cells, tissues,
organs and systems are therefore studied by biologists, who then inform our understanding
of health.
Anatomical orientation: Cavities
and the organisation of the body
Finally, the tissues and organs are found in various locations in the body. These locations can be
categorised or described in a number of ways.
There are detailed anatomical descriptions
to make locations precise and orienteering
accurate. Below are some common anatomical
terms and their meanings:
It can also be divided into cavities (from the
word cavernous or cave) or gaps, which identify
where organs can be found. The six cavities are
(also see Figure 1.12)
superior – above,
inferior – below,
anterior – in front of,
posterior – behind,
medial – on the inner side of,
lateral – on the outer side of,
proximal – close to,
distal – farther from,
superficial – at the body surface,
deep – away from the body surface,
dorsal – to the front,
ventral – to the rear,
rostral – to the head and
caudal – to the tail.
The body can be divided, simply, into three
9781403_945471_02_cha01.indd 31
trunk and
appendages (arms and legs).
abdominal and
Health Connection
Anatomical terms
Anatomical terms help us to
navigate around the body and are
used clinically to be precise about
where an injury, intervention or
treatment occurs.
The position on a body can also be described by
regions (body areas) (Table 1.4).
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Cranial cavity
– contains brain
Thoracic cavity
– contains heart (in pericardial cavity)
– contain lungs (in pleural cavity)
Abdominal cavity
– contains digestive system
Pelvic cavity
– contains bladder
– contains rectum
– contains reproductive system
Body cavities
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Table 1.4 Anatomical terms and their body regions
Anatomical term
Body regions
Anterior body trunk inferior to ribs
Fingers, toes
Area where thigh meets body trunk; groin
Nose area
Area overlying the pelvis anteriorly
Breastbone area
Neck region
Curve of shoulder formed by deltoid muscle
Area of back between ribs and hips
Posterior surface of head
Posterior area between hips
Conclusion: Maintaining a
safe environment
We live in an indifferent external environment in which we coexist with many other
species of organisms all trying to survive and
thrive. In a multicellular organism such as
humans, our cells coexist in a community,
each one trying to survive and thrive as well as
contribute to our total survival; each competing and cooperating to increase its individual
and our collective chances of living. Variables,
9781403_945471_02_cha01.indd 33
by their nature, vary. Those in the external
environment we cannot really control, but we
must control the internal ones to maximise
our chances of survival and keep ourselves as
safe as possible. Homeostasis is the mechanism that measures our variables, reports any
changes and motivates us to maintain optimal
conditions. When all of this is in place our
internal environment is relatively safe and we
are healthy and able to carry out all the ADLs
that allow us to interact with our environment
and be alive.
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Chapter Summary
This chapter introduces the concept of homeostasis (self-maintenance).
Homeostasis allows biological living processes to be carried out to maintain the organism.
In health homeostasis allows us to maintain our own internal environment so that we may carry out the needed activities of daily living (ADLs)
that allow us to function.
The external environment fluctuates and is not ideal for our bodies.
Our internal environment fluctuates due to metabolic processes.
All living processes are carried out to maintain our internal environment.
Homeostasis links our internal needs to the external environment.
Homeostasis links our health to our safety.
We are formed from cells and have formed all the cells of our bodies
using the raw material of the universe, chemicals.
Cells have a plasma or cell membrane, cytoplasm and organelles.
Differentiation is a process that allows cells to have variety from a generic
Different cells vary in their shape, size and lifespan.
Different types of cells form different types of tissues.
We have many types of cell, but they are categorised into four types
called tissues.
These four types are epithelial, connective, muscle and nervous.
The four types have different anatomical shapes from the generic cell.
The anatomical differences allow different physiological functions (processes) to be performed.
The large organs of our bodies are formed from tissues which are formed
from cells.
Organs carry out the functions of our bodies in groups called systems.
Some organs are formed of one tissue type only; e.g. glands are made
from epithelial tissue.
Other organs are made of two types of tissue, e.g. membranes, skin.
Most organs are made of many tissue types; e.g. the heart is made mainly
of cardiac muscle, but also has connective tissue, and the inner tubes
with blood flowing through are lined with epithelial tissue.
Surrounding many organs are membranes that protect and hold organs
in place.
The body can be oriented through descriptive terms to help locate tissues
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NOTE: Page references in italics refer to figures and tables.
ABO blood groups, 213–15
absolute zero, 54
acclimatisation, 152
acetylcholine (ACh), 173
ACh, see acetylcholine
acid-base balance, 48–50, 60
acne, 156
acquired immunity, 309, 317–18, 319
actin, 171
action potentials, 104, 105–7, 111
active transport, 19, 21
activities of daily living (ADL), 3, 358
body temperature as, 142–3
breathing, 184, 204
cells and, 13
cleansing and dressing, 299, 322–3
communication, 102, 141
control and repair, 142, 161–2
death, 340, 357–8
eating and drinking, 241–2, 280–1
energy and, 147
growth and development, 64–5, 66,
homeostasis and, 4
movement, 163, 183
routines, 325
sleeping and healing, 324, 338–9
transportation, 205, 240
waste elimination, 282, 297–8
work and play, 35, 62–3
acute pain, 329
acute renal failure, 289
adaptive immune system, 311, 315–21
Addison’s syndrome, 138, 139
adenosine diphosphate (ADP), 53, 145–6, 246
adenosine triphosphate (ATP), 12, 52–3, 108, 184,
242, 246
breathing and, 185–6, 203
exercise and, 252
heat production and, 145–150
muscle contraction and, 174–6
ADH, see antidiuretic hormones
ADL, see activities of daily living
ADP, see adenosine diphosphate
adrenal cortex, hormone secretion, 137, 138
adrenaline, 110, 117, 137
adrenal medulla, hormone secretion, 117, 137
aerobic respiration, 174
biological aspects, 348–50
diseases, 352–4
normal, 350–2
airflow measurement, 197
air pollutants/pollution, 188
air pressure, 186–7
airway resistance, 201
alcohol consumption
ADH and, 291
effect on brain, 131
urine formation and, 296
aldosterones, 292
alleles, 74–6
dominant and recessive, 80–3
allergies, 321
alveoli, 192, 198
amino acids, 55, 59–60, 67–8, 244–5
translation, 68–72
transportation, 270–1
amniocentesis, 97
anabolic reactions, 51–2, 146
anabolic substances, 54
anaemia, 209
sickle cell, 210
anaerobic glycolysis, 174
anaesthesia/anaesthetics, 332
dermatomes and, 121–2
ion channels and, 107
anatomical terms, 31–3
angina, 232, 234
anions, 43, 44
ANS, see autonomic nervous system
antagonists, 333
anterior pituitary glands, 135–6
antibiotics, 274, 301
resistance to, 321
9781403_945471_15_ind.indd 359
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36 0
antibodies, 213
action on antigens, 316–7
antidiuretic hormones (ADH), 138, 291
antigens, 213–14, 310
B lymphocytes and, 316–18
recognition, 316
antioxidants, 245
apoptosis, 15, 160
treatments and, 19
appendicitis, 273
appendicular skeletons, 165
arrhythmia, 232
arteries, 220, 223–4, 229–30, 231
carotid, 233
vertebral, 233
arterioles, 230–1
arthritis, 168–9
asepsis, 305
aspirin, 313
asthma, 195
atherosclerosis, 232–3, 233, 238, 240, 353
atmospheric pressure, 187
atom(s), 37–9
atomic number, 39
ATP, see adenosine triphosphate
atria, 220, 223, 224
atrioventricular valves, 220
autoimmune diseases, 309, 310
autonomic nervous system (ANS), 111, 117–19
thermoregulation, 151
autonomic reflexes, 118, 119
axial skeletons, 167
axons, 105
large intestine, 253, 273–4
pathogenic, 274, 301
ulcers and, 265, 275
urethra and bladder, 296
balance, see posture and balance
baro-receptors, 117
basale, 155
basal ganglia, 130, 177
basal metabolic rates (BMR), 146, 252
basophils, 308, 312
BAT, see brown adipose tissues
bicarbonate, 292
bile, 267, 268–9, 270
biological organisation levels, 10, 11
bipedal animals, 163–4
bladders, 286
stones, 295
waste elimination, 293–4
9781403_945471_15_ind.indd 360
blastocysts, 91
blood, 218
cardiac output, 227–8, 236–7
circulation, 219, 221–2, 232–4
composition, 206–7
counts, 207
diseases, 208, 209–10, 211, 212
functions, 206
waste removal, 286–9
blood-brain barrier, 132–3, 233
injected dopamine and, 130
blood cells, 207–8, 209
production rate, 208
see also megakaryocytes; red blood cells;
white blood cells
blood clotting/clots, 211–13
embolisms and, 234
blood gases, pH and, 50
blood groups, 213–15
blood pressure (BP), 236–7
ADH and, 138
lifespan changes, 239
measurement, 238–9
peripheral resistance and, 237–8
water loss and, 277
blood transfusion, 214–15, 232
blood vessels, 220, 232
ageing, 351
functions, 231–2
B lymphocytes, 315–18
BMR, see basal metabolic rates
body organisation, 31–3
body temperature, 162
as ADL, 142–3
environment and, 143
fever, 55, 153, 313
normal range, 61
see also thermoregulation
ageing, 350–1
functions, 131, 132, 165–7
funny bone, 112
types, 167–8
see also joints
bone marrow, 168, 208–9, 306–7
bowel movements, fibres and, 253
BP, see blood pressure
brain, 124–31
ageing, 351
damage, 132
endocrine system and, 135
excess alcohol consumption impact
on, 131
homeostatic control, 6–7
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brain death, 355
brainstem and, 126
oxygen and, 108
brainstem, 126
activity, 326
breathing regulation, 199–200
breathing, 184–5, 188, 204
cessation, 185–6
homeostatic control, 199–201
mechanism, 194–5
micro-organisms and, 300
vital capacity, 196–7
Broca’s area, 126
damage, 129
bronchi, 192
bronchioles, 191–2
bronchitis, 192, 193, 354
brown adipose tissues (BAT), 152
bulimia, 264
burns, 157, 303
caesarean section, 94
calcitonin, 136
ageing and, 351
level regulation, 136–7
calories, 145, 146, 242, 251, 280
average requirement, 253
cancellous bone tissues, 166, 167
blood, 208
cellular communication and, 133
epidemiology, 345
gastrointestinal tract, 257
lung, 203
skin, 158
stem cells and, 94–5
tissue and, 26
tissue repair and, 29
carbohydrates, 55, 56, 243–4
average requirement, 253
digestion in small intestine, 268–9
carbon, 36, 38, 55–6
covalent bond, 47
in food, 242
carbon dioxide (CO2), 185–6
elimination, 211, 284
carcinomas, 29, 257
cardiac muscles, 170
cardiac output, 228–9
activities impact on, 228–9, 234–5
ageing, 351
cardiovascular shock, 352
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cardiovascular system, 219–29
diseases, 219, 221, 231–2, 234, 238–9
cartilaginous joints, 168
catabolic reactions, 51–2, 145, 146
catheters, 296
cations, 43, 50
cavities, 31–2
cell(s), 10–12, 19, 24
communication, 133–4
daughter cells, 29, 79, 94–5
death, see apoptosis
division, 79, 79
endocrine, 135
formation and loss, 153–4
goblet cells, 190
immunity, 315
lifespan, 18, 37
nervous system, 104–10
overproduction, 162
respiration, 147, 148, 185, 198
shapes, 15–16, 18
size, 15–17
structure, 12–15
types, 24–6
see also homeostasis
cell cycle ageing, 349
cell membrane, 12–13
cellular metabolism, 11–12, 18–19
ageing and, 349
cellular transport, 18–19, 24, 205
types, 19–23
cellulose, 253, 263
Celsius, 54–5
central nervous system (CNS), 120–31
cerebral circulation, 233–4
cerebral lobes, 126
cerebrospinal fluid (CSF), 131–2
hydrogen ions, 200
cerebrum, 124, 126–9
chemical(s), 11–13, 36–7
immune system, 306
as messengers, 133–4
chemical digestion, 263–6
of nutrients in small intestine, 268–9
chemical formulas, 45–6
chemical reactions, 51–2, 54–5
chemical-receptors, 117
chemoreceptors, 200
chemotherapy, 19
chewing, 259, 260
chlamydia, 301
chlorine, 43–4
cholesterol, 15, 56, 57, 244
average requirement, 253
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36 2
cholesterol – continued
functions, 271
chorionic villi sampling, 97
chromosomal disorders, 78, 80
oocyte production and, 89
screening, 97
chromosomes, 14, 76–8
chronic obstructive pulmonary disorder (COPD),
chronic pain, 329
chronic renal failure, 288
chylomicrons, 270
cilia, 15, 190, 191, 300
circadian rhythms, 326
cleansing and dressing, 299, 322–3
climate, 187
clinical investigations, 357
clonal expansion, 316, 317
CNS, see central nervous system
coagulation, 211
control, 212
codons, 69–70, 71, 77
co-enzymes, 149
colds, impact on smell and taste, 116, 190
colloidal osmotic pressure, 217
colonic stomas and bags, 275
coma, 130, 355–6
commensals, 253, 273, 300–1
communication, 102, 141
compact bone tissues, 166, 167, 180
complement proteins, 314–5
compounds, 40–1
formation, 44
conception, 66
conchae, 190
conduction (heat), 144
confounding variables, 344
congenital disorders, 80
foetal development and, 93
hole in the heart, 221
connective tissues, 25
consciousness, 129–30
see also coma
constipation, 182, 253
see also fibres
contact-mediated toxicity, 314
contraceptive pills, 140
control and repair, 142, 161–2
skin, 154–61
convection (heat), 145
COPD, see chronic obstructive pulmonary disorder
corneum, 154–5, 157
9781403_945471_15_ind.indd 362
coronary circulation, 232–3
coronary heart diseases, 232
coronary thrombosis, 232
corpus callosum, 124, 126
cortex, 126
corticosteroids, 137, 138
cot death, 201
coughing, 191
covalent bonds, 46–8
cranial bones, 131, 132
cranial nerves, 124–5
creatine phosphates, 174
Crick, Francis, 73
CSF, see cerebrospinal fluid
Cushing’s syndrome, 138
cutaneous membranes, 29
cyanobacteria, 301
cystic fibrosis, 83, 202
cystitis, 296
cytokines, 133–4
cytoplasm, 12, 14–15
red blood cells, 208
cytoskeleton, 14
cytotoxic T cells, 319, 320
Darwin’s theory of evolution, 341
death, 340–1, 357–8
biological aspects, 342–3
causes, 346–8
clinical, 354–5
defining, 355–6
immediate cause, 354
voluntary aiding, 356
deep pain, 329
dehydration, 9, 23, 51, 274
delayed hypersensitivity, 321
dementia, 129
demyelination, 108
dendrites, 105
deoxyribose nucleic acids (DNA), 14, 55, 68–70,
synthesis, 73–5, 79
dependent variables, 344
dermatomes, 121–3, 178
dermis, 156–7
diabetesinsipidus, 291
diabetes mellitus, 137, 272
type II, 353
diabetic kidney diseases, 292
diagnosis, 9
WBCs count and, 308
3/12/2012 11:34:24 PM
dialysis, 293, 293
diaphragms, 195
diarrhoea, 274, 283
diastolic pressure, 238
diencephalon, 124
diet, 148, 243, 280
ageing and, 349
amino acids and, 68
atherosclerosis and, 240
essential amino acids from, 59, 67
healthy/balanced, 241, 252, 254
lifespan changes, 279–80
macromolecules and, 56
nutrients, 56–8
nutrients, lack in, 254
vitamins and minerals amount, 245
weight and, 251
diffusion, 19–21
see also osmosis
digestive system, 255–6
diseases, 257, 265, 274
lifespan changes, 279–80
diploids, 76, 79–80
diploid zygotes, 89
disaccharides, 243, 268–9
diseases/disorders, 84
adrenal cortex, 137–8, 139
ageing, 352–4
blood, 208, 209–10, 211, 212–13
cardiovascular system, 218, 221–2, 232–3, 234,
chromosomal, 78, 80, 89, 97
digestive system, 227, 266, 274, 277
endocrine system, 136, 137, 138–9
eye, 114
genetic screening, 84, 85, 97
infectious, see infections/infectious diseases
metabolic, 58, 264
mitochondrial, 15
movement, 180
musculoskeletal system, 168–9, 173, 175, 176–7,
178, 180
mutations and, 75
nature and variables, 343–7
nervous system, 108, 126, 128, 129–30, 132–3
recessive, 82, 83, 173
renal system, 288–9, 291, 292, 294–5, 295–6,
respiratory system, 190, 192, 193–4, 195, 199,
200, 201, 202
sex-linked, 82
skin, 155, 156, 158, 160, 161
9781403_945471_15_ind.indd 363
sleep-associated, 328
WBCs count and, 308
see also under individual diseases, e.g., cancers;
haemolytic anaemia
dislocations, 168
see also fractures
dizygotic twins, 90
DNA, seedeoxyribose nucleic acid
dominant genes, 80–3
dominant mutations, 82
dopamine, 130, 177
double-blind clinical trials, 331–2
Down’s syndrome, 78
dreams, 328
drowning, 54
drugs, 332
administrative sites, 332–3
aspirin, 313
chemical formulas and, 46
dosage, 334
half life, 333
mode of action, 333
pain, 331
tolerance and dependence, 334–5
types, 332
Duchene’s muscular dystrophy, 173
ears, 114–15
ageing, 352
balance and, 115–16
popping, 115
eating and drinking, 241–2, 255, 275–8, 280–1
see also food; water
ECG, see electrocardiogram
E coli, 296
ectopic pregnancy, 92
Edelman, Gerald, 130
effectors, 7
autonomic nervous system and, 118
feedbacks, 7–8
thermoregulation, 152
electricity, nervous system, 105, 106
electrocardiogram (ECG), 226, 228
electrolytes, 44, 46
electrons, 38–9, 41
electron transport chain, 149–50
elements, 37–9
electron shells, 41–3
Periodic Table, 39–41, 44–6
embolisms, 234
embryonic development, 66, 90–3
3/12/2012 11:34:24 PM
36 4
embryonic stem cells, see pluripotent stem cells
emphysema, 199
endocardium, 219
endocrine glands, 26, 134–5
growth and development, 141
see also under individual glands, e.g., pituitary
endocrine system
communication and, 134–40
diseases, 136, 137, 138–9
endocytosis, 21, 22
endogenous pyrogens, 153
endoplasmic reticulum, 15
energy, 35
estimated average requirements, 280
from food, 52–4, 145–50, 242, 251
kinetic, 54, 106, 144
for movement, 174–6
work and, 106–7
engulfment, 21–2
enkephalins, 337
enteroreceptors, 116, 117
entropy, 19
external, see external environment
internal, see internal environment
safe, 1–2, 33
sterile, 305
enzymes, 55, 58–9
ATPase, 107
digestion and, 263
pancreatic, 268, 272
small intestines, 267–8
eosinophils, 308, 309
epidemiology, 343–4, 345
epidurals, 124
epiglottis, 191, 260
epilepsy, 130
epiphyseal plates, 180
episodic memory, 129
epithalamus, 125
epithelial tissues, 24
repair, 29
erythrocytes, see red blood cells
essential amino acids, 59, 67
eugenics, 65–6, 85
euthanasia, 356
evaporation, 145
ageing, 349–50
Darwin’s theory, 341
nature or nurture debate, 65–6, 84–5
9781403_945471_15_ind.indd 364
excretion, see waste elimination
exercises, 349
ATP and, 252
respiratory rates, 203
exhalation, 185, 195–6
exocrine glands, 26–7, 134–5, 190
exocytosis, 21, 22
external environment, 1, 4–5
body temperature and, 143
breathing and, 186–8
communication and, 102–3
death and, 340–1
growth/development and, 65
mobility and, 163
sensing, 112–17
sleep and, 324–5
transportation, 205
work/play and, 36–7
external respiration, 185, 198–9
extrafusal muscle fibres, 171
eyes, 113–14
ageing, 352
facilitated diffusion, 21
FAD+, seeflavin adenine dinucleotide
faeces, 253, 272–3, 275, 285–6
defecation, 285
diarrhoea, 274, 354
UTI and, 296
water loss, 277, 291
see also waste elimination; waste types
fascia, 170, 171
fat soluble vitamins, 245
feedback, see negative feedback; positive feedback
feedforward, 8–9
fertilisation, 90
in-vitro, 97
fertility, 99
fever, 55, 153, 313
fibres, 246, 252, 253, 285
extrafusal muscle, 171
fibrin, 211–12
fibrinogen, 211–12
fibrinolysis, 211
fibrous joints, 168
first pass effect, 333
flat bones, 167
flavin adenine dinucleotide (FAD+), 149–50
cerebrospinal, 131–2, 200
interstitial, 216, 217
3/12/2012 11:34:24 PM
pleural, 194, 195
serous, 27–8, 194, 195
synovial, 28, 28–9, 168
see also water
foetal development, 93
food, 241–2
digestion, 258–66
energy from, 52–4, 145–50
ingestion, 259
need, 246, 247
nutrients and, 242–6
required amount, 247
undigested, 283–4, 284
food chain, 300
food charts, 255
forensic science
DNA in, 73
integumentary system and, 159
forward movement, 180
fractures, 167
age factor and, 181
free radicals, 245, 343
ageing and, 349
fungi, 302
Galton, Francis, 85
gametes, 66, 86
gas exchange, 185, 192, 197–9
gastric bands, 261
gastrointestinal tract (GI tract), 255, 256–8, 275,
digestion mechanism, 258–61
functions, 258
removal of faeces from, 285
Gate theory of pain transmission, 338
gender, 98
puberty and, 99
realignment surgery, 99
genes, 14, 149
ageing and, 348
inheritance, 82–4
nature or nurture debate, 65–6, 84, 343
genetic coding, 68–73, 77
genetic diseases, 81–2, 83–4, 173, 202, 210, 264,
289, 348
treatment, 85
genetic screening, 84
IVF and, 85, 97
genotypes, 82–3
GFR, see glomerular filtration rate
GH, see growth hormones
9781403_945471_15_ind.indd 365
GI tract, see gastrointestinal tract
glands, 26–7
hormone secretion, 135–40
glaucoma, 114
glia, 104
glomerular filtration, 287–8
glomerular filtration rate (GFR), 290, 292
glomerulus, 287–9
glucagon, 137, 272
glucose, 146–7, 150, 184–6, 246–7, 247, 271–2
metabolism, 137
glycogen, 117, 137, 271
glycolysis, 147
anaerobic, 174
glycoproteins, 213
goblet cells, 190
Golgi apparatus, 15
Golgi tendon organs, 172
gonads, 66, 86
development, 98–9
gram staining, 301
granulocytes, 306, 308, 314
growth and development, 64–5, 66, 100–1
during lifespan, 140–1
embryonic, 90–3
foetal, 93
puberty, 98–9
skeletal system, 180–2
growth hormone(s) (GH), 181
growth hormone disorder, 136
haematopoiesis, 168
haematopoietic stem cells (HSC), 208
haemocytoblast stem cells, 306
haemoglobin, 16, 208, 210
lifespan changes, 215
oxygen and, 210
haemolytic anaemia, 16
haemophilia, 212
haemorrhage, 212, 353
haemostasis, 206, 212
serum proteins and, 211
haploids, 76, 80
haptens, 321
Hawking, Stephen, 120
hay fever, 321
homeostasis and, 5–10
illness and, 31
safety and, 1–3
water and, 23
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36 6
hearing, 114–16
heart, 219–21, 240
damaged valves, 224
functions, 221–2
hole, 221
pumping mechanism, 225–9
sounds, 225
heart beat, 225, 235–6
heart rate, 227–8, 239
heat, 54–5, 144–5
acclimatisation, 152
loss, 150
production, 145–50
heat exhaustion, 153
heat stroke, 153
heliobacter pylori, 265, 275
helper T cells, 319, 320
hip replacement, 181
HIV, 320
activities of daily living and, 4
control/maintenance, 5–9
etymology, 2
fever and, 314
notion, 1–2, 10
thermoregulation and, 150–2
homeotherms, 143
hormone(s), 117, 134–5
glands and, 135–40
producing structures, 141
release, control of, 135
hormone replacement therapy, menopause and,
HSC, see haematopoietic stem cells
HUGO, see Human Genome Project
human body
changes during pregnancy, 97–8
percentage of elements in, 38
systems and organs, 29–30
see also under individual systems and organs, e.g.,
nervous system; lungs
Human Genome Project (HUGO), 79
humoral immunity, 315
Huntington’s disease, 84
hydrochloric acid, 265
hydrogen bonds, 48, 60
hydrogen ions, 48–50
in cerebrospinal fluid, 200
hydrostatic pressure, 217
hypersensitivity, 321
hyperthermia, 153
hypnosis, 331
9781403_945471_15_ind.indd 366
hypothalamus, 117, 118, 124, 135
thermoregulation, 151
hypothermia, 153
ICM, see inner cell mass
ill health/illness, 9, 31
immediate hypersensitivity, 321
immobility, 164
immune surveillance, 206
immune system, 304, 306–9
lifespan changes, 322
immunoglobulins, see antibodies
induced pluripotent stem cells (iPSC), 96
inert gases, 41, 43
infant mortality rates, 344
infants, see newborns and infants
infections/infectious diseases, 299, 302–3
detection and prevention, 309–11
epidemiological parameters, 345
nosocomial, 299, 302
viral, 319–20
see also pathogens
inflammations, 312–13
pain and, 338
ingestion, 259
inhalation, 185, 195–6
inheritance, 82–4
innate immune system, 311–15
inner cell mass (ICM), 93, 95
innervation, 119, 172–3, 175, 177, 178, 200, 228
electricity and, 105, 226
insensible water loss, 152
insomnia, 328
insulin, 137, 272
interferon, 313, 314
internal environment, 2, 5
body temperature and, 143
breathing and, 184–5
communication and, 103–4
death and, 341–2
growth/development and, 65–6
sensing, 117–19
sleep and, 325
transportation, 205–6
variables, 5–6
work/play and, 36–7
see also homeostasis
internal respiration, 185, 198–9
interneurons, 121
interstitial fluids, 216, 217
intrafusal muscle fibres, 171–2
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intramuscular injections, 171
in-vitro fertilisation (IVF), 85, 97
ion(s), 41, 43, 45, 107
hydrogen ions, 48–50
ion channels, anaesthetics and, 107
ionic bonds, 44
irregular bones, 167
islets of Langerhans, 137
isometric contractions, 173–4
isotonic contractions, 173
IVF, see in-vitro fertilisation
joints, 168–9, 180
see also bones
juxtaglomerular apparatus, 290
karyotypes, 77–8
keratin, 154–5, 157
kidneys, 286
ageing, 352
dialysis, 293, 293
regulation of functions of, 290
role in metabolic waste removal,
286–893kidney stones, 288
kinetic energy, 54, 106, 144
Krebs cycle, 147–9
labour/childbirth, 93–4
lactic acid, 147, 343
anaerobic respiration and, 175, 176
lactose intolerance, 265, 280
large intestines, 272–5
waste elimination, 284–5
laryngopharynx, 191
larynx, 191, 260
latex gloves, 304
learning difficulties, 130
leg ulcers, 161
leucocytes, see white blood cells
leukaemia, 208
life expectancy, 345–6
lifespan, 37
blood pressure changes, 239
cells, 16
diet changes, 280
digestive system changes, 280
haemoglobin changes, 215–16
heart rate changes, 239
immune system changes, 322
9781403_945471_15_ind.indd 367
increasing, 348
integumentary system changes, 159–61
maximum, 348
nervous and endocrine system changes, 140–1
renal system changes, 296
respiratory system changes, 201–3
skeletal system changes, 180–2
sleep amount, 327–8
water content changes, 280
ligaments, 170, 171
lipids, 12–13, 56–7, 244
digestion in small intestine, 270
skin, 157
lipofuscin, 349, 352
liver, 266–7, 268, 269
drugs and, 333
fats in, 271–2
living processes, 3, 358
impact of temperature on, 61
living things, 3
locked in syndrome, 355–6
long bones, 167, 168
long-term memory, 129
lungs, 191–2
ageing, 351
air intake mechanism, 193–4
average volumes in litres, 197
breathing mechanism, 194–6
cancer, 203
compliance, 201
maintenance of pressure difference, 196
lymph, 216, 217–18
fats and, 271
lymphatics, 216
lymphatic system, 216–18
lymphocytes, 218, 306, 308, 309
types, 315–16
lymphoid system, 306
lysosomes, 15, 311, 349
macromolecules, 37, 55–8
macrophages, 160, 209, 306, 311, 313
major histocompatibility complex (MHC), 309
T lymphocytes and, 320
malnutrition, 254
mammary glands, 140
manual handling, 182
airflow, 197
blood oxygen, 201
blood pressure, 238
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36 8
measurement – continued
pain, 330
pulse, 236
respiratory rates, 197
mechanical digestion, 259–60, 261–3
megakaryocytes, 207
meiosis, 80
oocytes, 89
melanin, 154, 155, 157
melanocytes, 154, 155, 157
membrane(s), 27
types, 27–9
membrane potential, see resting potential
brain and, 129
immune system, 309, 317–18, 319
memory B cells, 315, 316–17
meninges, 131, 132
meningitis, 133
menopause, 100
menstruation and menstrual cycle, 89–90, 139–40
miscarriage and, 91
mental health, communication and, 103
messenger RNA (mRNA), 71
metabolic diseases, enzymes and, 58
metabolic rates, 146
metabolic waste, 283, 284
elimination, 284
elimination from kidneys, 286–93
metabolism, 51–2, 247, 251–2
cell, 11–12, 18–19
glucose, 137
thermoregulation and, 144–50
thyroid glands and, 136
metals, 44, 46
metaphase spread, 77
methicillin-resistant staphylococcal infections
(MRSA), 302
MHC, see major histocompatibility complex
micro-organisms, 299
breathing and, 188, 300
food chain and, 300
osmosis and, 314
types, 300–1
microvilli, 15, 258, 266
minerals, see salts
miscarriage, 91
mitochondria, 14
mitochondrial diseases, 14
mitosis, 79, 79
MND, see motor neuron disease
molecules, 37
3D structure, 48, 55
9781403_945471_15_ind.indd 368
monoglycerides, 270
monosaccharides, 55, 243, 244
transportation, 270
monozygotic identical twins, 91
morbidity rates, 345
mortality rates, 346
motion sickness, 116
motivation, homeostasis and, 9
motor cortex, 128, 177
motor neuron(s), 111, 173–4
motor neuron disease (MND), 120, 173
motor outputs, 119
motor units, 129
mouth and teeth
chemical digestion, 264
mechanical digestion, 259–60
movement and mobility, 163, 183
directions of, 176
energy, 174–6
types, 176–80
movement disorders, 130
mRNA, see messenger RNA
MRSA, see methicillin-resistant staphylococcal
mucosa/mucous membranes, 27, 28, 190, 257,
multiple sclerosis, 310
demyelination and, 108
multipotent stem cells, see somatic stem cells
muscle contractions, 172–3
energy, 174–6
muscle degeneration, 181
muscle fatigue, 175
muscle system, 170–4, 183
ageing, 350
blood circulation, 234
muscle tissue cells, 26
mutations, 14, 74–6
dominant, 82
myasthenia gravis, 175, 310
mycoplasmas, 301
myelin, 105, 108
myocardial infarction, 220, 232, 234
myocardial ischaemia, 232
myocardium, 219
myosin, 171
NA, see nucleic acids
NAD+, see nicotinamide adenine dinucleotide
naso-gastric tubes, 260
nasopharynx, 191
natural killer (NK) cells, 209, 308, 314
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natural selection, 65–6, 84–5, 341
necrosis, 160, 284
negative feedback, 7–8
hormone release regulation, 135
negative fluid balance, 278–9
nephrons, 286, 289
nervous system, 104
breathing control, 199–201, 202
cells, 104–10
diseases/disorders, 108, 126, 128, 130, 132, 133
growth and development, 140–1
lifespan changes, 140–1
organisation, 110–31
protection, 131–3
nervous tissue cells, 25, 26
neurons, 104–10
motor, 111, 173–4
sensory, 111, 179
neurotransmitters, 108–9, 118
dopamine as, 130
neutral atoms, 38–9
neutrons, 38, 39
neutrophils, 308, 311, 313
newborns and infants
blood pressure, 239
calorie requirements, 280
GI tract, 280
heart rate, 239
immune system, 322
lungs, 201
respiratory rate, 201
sleep amount, 327–8
thermoregulation, 152
waste elimination, 296
nicotinamide adenine dinucleotide (NAD+),
nicotine, 110
patches, 158
NK cells, see natural killer cells
noble gases, see inert gases
nociceptive movements, 178
nociceptors, 116, 178, 335–6
nodes of Ranvier, 105, 108
non-living things, 3
non-metals, 44, 46
non-REM sleep, 326
noradrenaline, 110, 117, 137
nose, 116, 117, 189–90
nosocomial infections, 299, 302
nucleic acids (NA), 67–8, 246
DNA, 13, 55, 67–70
RNA, 71–3
nucleotide bases, 68–9
9781403_945471_15_ind.indd 369
nucleus of cell, 12, 13–14
nutrients, 56–8, 242–6
absorption from small intestine, 270–2
average requirements, 253
chemical digestion in small intestine, 268–70
energy yield, 251
diet and, 254
mobility and, 182
old age, 353
occupational hazards, 1, 2
oedema, 164, 217
oesophagus, 191, 260–1
oestrogens, 139
oocytes, 80, 99
production, 87, 89–91
opiates, 337
organelles, 12, 14–15
organic chemistry, 47–8, 242
organs, 26, 29, 30
location, 31–3
transplantation, 310
transplantation types, 309
oropharynx, 191
osmosis, 22–3
micro-organisms and, 314
osteoarthritis, 169
osteoblasts, 180–1
osteoclasts, 180, 181
oxidation:reduction reactions, see redox reactions
oxygen, 185–6, 188
brain death and, 108
drowning and, 54
pressure, 187
red blood cells and, 210
pacemakers, 226
pain, 329, 335
components, 329–30
inflammation and, 338
management, 332
measurement, 330
suppression, 330
as symptom, 336
transmission, 337
treatment, 330–1
pain pathways, 336–7
pain receptors, 335
pain stimulus, 335–6
palliative care, 356
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37 0
pancreas, 255, 266, 269
endocrine and exocrine functions, 267–8
hormone secretion, 137
parasitic worms, 302
parasympathetic system, 118–19
parathyroid glands, hormone secretion, 136
parathyroid hormones (PTH), 136
parietal pericardium, 220
parietal pleura, 194, 195
Parkinson’s disease, 126, 130, 177
partial pressure, 187, 198
Pascal (Pa), 187
barriers to, 304
detection and prevention, 309–11, 316–17
resistance to antibiotics, 321
types, 301–3
pathology, 12
pepsin, 265
peptides, 55, 68
pericardium, 220
Periodic Table of elements, 39, 41
groups, 44–5
peripheral nervous system (PNS), 110–20
peripheral resistance, 237–8
peristalsis, 257, 259, 263, 293
persistent vegetative states (PVS), 355
phagocytosis, 311, 314
pharmacology, 332–5
cellular transport and, 22
lifespan changes and, 140–1
synapses and, 110
pharynx, 190–1, 260
phenotypes, 82–3
phenylketonuria (PKU), 58, 264
phospholipids, 244
pH scale, 48–50
physical states, 54
physiotherapy, 167
weightlessness and, 165
pituitary glands, 117, 124
hormone secretion, 135–6, 138
PKU, see phenylketonuria
placebo, 330–1
placenta, 91–3
plant fats, 244
plasma, 206–7
plasma cells, 315, 316
plasma membrane, see cell membrane
plasma proteins, 207
complement, 314–15
platelet plug formation, 211
9781403_945471_15_ind.indd 370
pleura, 192, 194
pleural fluids, 194, 195
pleural membrane, 194
plicae, 266
pluripotent stem cells (PSC), 95, 96
pneumonia, 194
mycoplasma pneumoniae, 301
PNS, see peripheral nervous system
poikilotherms, 143
polar bonds, 48
polycystic kidney disease, 289
polymers, 55
polysaccharides, 55, 243–4
population, 342
positive feedback, 8
posterior pituitary, 136
posture and balance, 115–16, 178–80
potential difference, 106–8
pregnancy, 97–8
diet, 252, 280
ectopic, 92
Rhesus negative mothers, 215–16
stretch marks, 156
pressure, 164–5, 186–7
atmospheric, 187
blood, 138, 236–9
colloidal osmotic, 217
hydrostatic, 217
partial, 187, 198
pressure sores, 161, 165
procedural memory, 129
progeria, 348
progesterones, 139
proprioception, 171–2
proprioceptors, 116
prostaglandins, 312
protective clothing, 303
proteins, 67–8, 244–5
digestion in small intestine, 268
facilitated diffusion and, 21
gene coding and, 68–73
genes and, 14
shape and function, 59, 60, 67, 71–2, 143–4
see also enzymes; individual proteins, e.g.,
prothrombin, 211–12
protons, 38–9
protozoa, 302
PSC, see pluripotent stem cells
psoriasis, 160
PTH, see parathyroid hormones
puberty, 98–9
3/12/2012 11:34:25 PM
pulmonary capillaries, 198, 224
pulmonary circulation, 221–4
pulse, 235–6
measurement, 235
points, 236
pulse oximeters, 201
PVS, see persistent vegetative states
pyruvic acid, 147
radiation, 144
radio-isotopes, 40
rare earth metals, 39
RBC, see red blood cells
receptors, 6–7
recessive disorders, 82, 83, 173
recessive genes, 80–4
red blood cells (RBC), 206, 207–10
disorders, 210, 211
shape, 16
size, 16
redox reactions, 147, 149–50
reductionism, 71
referred pain, 329–30
reflex arc, 177, 179
reflex movements, 119, 177–8
refractory period, 107
regeneration, skin, 159–60
regenerative medicine, stem cells and, 96
REM sleep, 326
newborns, 328
renal system, 286
diseases, 288–9, 291, 292, 294, 295, 296
lifespan changes, 296
renin, 265, 290, 292
replication (genetics), 73–4, 79
reproduction, 85–6
reproductive system
female, 87, 89–90
growth and development, 98–9
male, 86–7, 88
respiration, 188
respiratory acidosis, 200, 353–4
respiratory membranes, 192, 193, 209
respiratory rates (RR), 196
exercise, 203
lifespan changes, 201
measurement, 197
sleep, 203
respiratory system, 185–93
diseases, 190, 192, 193–4, 195, 199, 200, 201,
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lifespan changes, 201–3
resting potential, 107–8
reticular formation, 326
retinal detachment, 114
retinopathies, 114
Rhesus blood groups, 213–16
rheumatoid arthritis, 168, 310
rhythmic activities, 177–8
ribose nucleic acids (RNA), 71–3
ribosomes, 14
rickettsia, 301
roughage, see fibres
RR, see respiratory rates
salivary glands, 255, 264, 265
salts, 44, 46, 245
nutrition and, 50, 250
sarcomas, 29, 257
saturated fats, 47, 56, 244
average requirement, 253
scar tissues, 29
Schwann cells, 105
amniocentesis, 97
chorionic villi sampling, 97
genetic, 84, 85, 97
sebum, 157
selective breeding, 65–6, 84–6
semantic memory, 129
sensations, skin and, 157–8
sense organs, 112–17
ageing, 352
sensory impairment, 113
external environment and, 103
sensory information, 110–17
cranial nerves and, 124
sensory neurons, 111, 177
serosa/serous membranes, 27–9, 257
serous fluids, 27, 194, 195
serum, 207
serum proteins, haemostasis and, 211
sex, 64–5
sex chromosomes, 76–80, 98
gender realignment, 99
sex glands, hormone secretion, 138–40
sex-linked diseases, 82
sexuality, 100
shivering, 152
short bones, 167
short-term memory, 129
shunts, 234
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37 2
sickle cell anaemia, 210
sinusitis, 190
skeletal muscles, 119, 170
structure, 170–2
skeletal system, 165–9, 183
lifespan changes, 180–2
skin, 5, 154
ageing, 350
blood circulation, 234
cancer, 158
diseases/infections, 155, 156, 158, 160, 161, 303
function, 157–8
repair and replacement, 159–61, 305
structure, 154–6
sleep, 324–6, 338–9
amount, 327
functions, 327
lifespan changes, 327–8
respiratory rate, 203
stages, 326
sleep apnoea, 203
sleep deprivation, effects, 326, 327
small intestines
absorption of nutrients from, 270–2
chemical digestion, 266
chemical digestion of nutrients, 268–70
enzymatic secretions, 267
surface area, 266–7
smell, 116, 117, 190
smoking, 240
smooth muscles, 170
sodium, 41, 43
average requirement, 253
homeostatic regulation, 291–3
somatic nervous system, 119–20
somatic reflexes, 119
somatic stem cells, 94, 95
somatosensory cortex, 126–8
speech, and brain, 129
sperm production, 86–7, 88, 99
spinal cord, 120–3
injuries and damages, 122, 178
rhythmic activities and, 177–8
sprains and strains, 170, 171
sqamous, 154
stem cells, 94, 257, 306
differentiation, 86, 95–6
types, 94–6
sterile environment, 305
steroid hormones, 137–40, 244
stethoscopes, 225
chemical digestion, 264–6
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mechanical digestion, 261–3
stretch marks, 156
stretch receptors, 171–2, 177
bladder, 294
stomach, 261
stretch reflexes, 177
stroke, 128, 233, 353
heat, 153
stroke volume, 227–9
subatomic particles, 38
sudden infant death syndrome (SIDS), see cot death
sugars, 55, 57, 243
suicide, 356
sulci, 236
sunbathing, 157
superficial pain, 329
suppressor T cells, 319, 320
surface tension, 201
surfactants, 197–8, 201, 202
gender realignment, 99
infections risk and, 303
pain and, 331
swallowing, 260
sweat, 157, 158
sympathetic system, 118
symptoms, 9
pain as, 336
synapses, 108, 110, 118
synovial fluids, 28, 28, 168
synovial joints, 168
synovial membranes, 28
systemic circulation, 221–4
systolic pressure, 238
target cell receptors, 134–5
taste, 116, 117
TCA cycle, see Krebs cycle
telomeres, 349
temperature, 54–5, 60, 143, 144
body, see body temperature
regulation, see thermoregulation
tendons, 170–1
TENS, see transcutaneous electrical nerve
testosterones, 139
thalassaemia, 211
thalamus, 124
thermoreceptors, 6, 117, 151
thermoregulation, 6
ageing and, 352
homeostatic mechanism, 150–2
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mechanism, 7–8
metabolism and, 144–50
need, 143–4
newborns, 152–3
skin, 158
thrombin, 211–12
thromboplastin, 212
thyroid glands, hormone secretion, 136
thyroxine, 136
time, and sleep, 324–5
tissues, 24–6
repair, 29
see also under individual tissues, e.g., cancellous
bone tissues
T lymphocytes, 316, 319–21
types, 319
TMR, see total metabolic rates
tongue, 116, 117, 260, 261
total energy expenditure, 145
total metabolic rates (TMR), 146
totipotent stem cells, 94
touch, 337
trachea, 191, 260
tracheotomy, 192
traffic accidents, 342
sleep and, 327
transcription, 71–2
transcutaneous electrical nerve stimulation (TENS),
331, 338
translation (genetics), 68–70
transportation, 205–6, 240
see also cellular transport
chemotherapy, 19
genetic diseases, 85
hormone replacement, 100
pain, 330–1
psychological help, 331
weightlessness, 165
see also drugs; surgery
triglycerides, 56, 57, 244
Turner’s syndrome, 78
dizygotic, 90
monozygotic identical, 91
two point discrimination tests, 129
ulcers, 265, 275
undigested food, 282–3
elimination from bowel, 284
unsaturated fats, 47, 56, 244
upper respiratory tracts, 188–92
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urethra, 286, 293–4
urinary incontinence, 294
urinary retention, 295
urinary tract infections (UTI), 296
urine, 295
abnormal constituents, 295
formation, 287–8, 290–1
voiding, 294
uterine/fallopian tube, 87
damage, 99
uterus, 87, 89–90
UTI, see urinary tract infections
vaccination, 317–18
valence shell, 41
atrioventricular, 220
heart, 224
dependent and confounding, 344
external, 4–5
internal, 5–7
normal ranges, 61
vascular system, 229–32
vasoconstriction, 151–2, 211
vasodilation, 151
veins, 220, 231, 231
venous return, 234–5
ventilation, see breathing
ventricles, 220, 223–4
venules, 231
villi, 258, 266
viral infections, 319–20
viruses, 302, 319
visceral pain, 329
visceral pericardium, 220
visceral pleura, 194, 195
vision, 113–14
vital capacity, 196–7
vital signs, 3
normal values and ranges, 62
vitamin(s), 158, 245, 248–9
excess, 245
vitamin B, 274
vitamin C, 160
vitamin D, 351
synthesis, 158
vitamin K, 274
vitiligo, 155
voice-box, 191
voluntary movements, 177, 178
vomiting, 116, 261, 264, 265
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37 4
washing, need and importance, 299
waste elimination, 52–3, 185–6, 203, 211, 253,
282, 297–8
from bladder, 293–4
from kidneys, 286–93
by large intestine, 253, 273–4
mechanism, 284
need, 283–4
through skin, 158
waste types, 282–3
see also under individual wastes, e.g., urine
water, 277–8
absorption by large intestine, 274, 284–5
absorption by small intestine, 270
ADH and, 138
cellular transport, 22–3
characteristics, 50–1
health and, 23
homeostatic regulation, 290–1
in human body, 278, 280
loss, 152
replacement, 23
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salty, 314
skin and, 157
water balance, 278–9
regulation, 279
water soluble vitamins, 245
Watson, James, 73
wavelengths, 112–13
WBC, see white blood cells
weight, 164–5
bulimia and, 264
diet and, 251
Wernicke’s area, 129
white blood cells (WBC), 206, 207
count, 308
functions, 308–9
types, 306–7
work and play, 35, 62–3
wound healing, 29, 305
ageing and, 349
nutrition and, 160
zeitgebers, 325
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