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HLTAP301A Recognise healthy body
systems in a health care context
Reading 1: Apply knowledge of the
basic structure of the healthy human
body
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© NSW DET 2007
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© NSW DET 2007
Contents
HLTAP301A Recognise healthy body systems in a health
care context
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Reading 1: Apply knowledge of the basic structure of the
healthy human body
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Contents
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Introduction
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Use accepted health terminology to describe the normal
structure, function and location of the major body systems
Health terminology
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Apply a basic understanding of the fundamental principles of
maintaining a healthy body
Organisation of the body
Internal cavities
Body regions
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Work with knowledge of the major components of each body
system and their location in relationship to other structures
Cardiovascular system
Respiratory system
Musculoskeletal system
Nervous system
Sensory system
Integumentary (skin) system
Gastrointestinal (digestive) system
Urinary system
Reproductive system
Endocrine system
Lymphatic and immune system
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Introduction
The human body is an amazing feat of biological architecture. It is designed
to not only ensure its own survival, but the survival of the human species.
The study of the human body is divided into two sections called anatomy
and physiology. Anatomy is the study of the structure or parts that make up
the body, whilst the physiology is concerned with their function.
Working with human beings whether young or old, you need a basic
understanding of the structure (anatomy) of the human body and how the
body works (physiology).
Understanding the human body’s normal functions, from the smallest cell in
the body to the body as a whole, allows you to start to comprehend what
happens to the person’s body through the ageing process as well as during
illness.
This knowledge can then be used to promote comfort, support and care of
older people in their activities of daily living (ADLs). It will also assist you
to understand signs, symptoms and the reasons for care and procedures
Use accepted health terminology to
describe the normal structure, function
and location of the major body systems
Communication skills are crucial to the delivery of quality care in the health
and aged care setting.
Understanding health/medical terminology is important in your work as an
aged care worker. As you gain more knowledge and experience you will
become familiar with and use health/medical terms when communicating
with other health team members. You will also medical terms in your
documentation.
Health terminology
Although health terminology can be sometimes hard to read and understand if you
break the word down you can work out what it means.
Many medical terms are a combination of smaller parts of words elements.
Terminology is easier to understand when larger words can be broken up into
smaller parts and elements. These elements are called prefixes, roots and suffixes
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Some examples of common medical terms combing these different word elements
are explained below
The word hyperglycaemia means higher than normal glucose in the blood.
Similarly, hypoglycaemia means lower than normal glucose in the blood.
Common medical terms and their word elements
Prefix
hyper
Root
Suffix
glyc
+
(high)
+
(glucose)
aemia
(blood)
Hyperglycaemia
(higher than normal glucose in the blood)
Prefix
hypo
Root
Suffix
glyc
+
(high)
+
(glucose)
aemia
(blood)
Hypoglycaemia
(lower than normal glucose in the blood)
When larger words are broken down into smaller parts it is easier to work out the
meaning of a word. Learning these word elements will help you work out the
meanings of difficult medical terms.
Definitions of prefix, root and suffix
Word element
Description
Prefix
Can be added to the beginning of root words to add further
meaning
Root word
The essential meaning of the term
Suffix
Can be added to the ending of root words to add further
meaning
Some common health terminology
Word root, prefix or suffix
Meaning
aathro-
joint
adip-
fat
-algia
pain
angio-
vessel
anterior
toward the front- ventral
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cardi-, cardio-, cardia-
heart
cephal-
head
cerebr-, cerebro-
brain
cut-
skin
dent-
teeth
derm-
skin
distal
away from point of attachment
-ectomy
excission
gastr-
stomach
genio-
chin
glosso-, -glossus
tongue
gyne-, gyno-
woman
hepato-
liver
histo-
tissue
homeo-, homo-
same
hyper-
above
hypo-
under
hyster-
uterus
inferior
lowermost or below
-itis
inflammation
lateral
toward the side of the body
lip-, lipo-
fat
mast-, masto-
breast
medial
nearest to the centre of the body
myo-
muscle
nas-
nose
nephr-
kidney
oculo-
eye
ophthalm-
eye
-opia
eye
-osis
state
osteon-, osteo-
bone
oto-
ear
patho-, -path, -pathy
disease
-phasia
speech
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Phleb-
vein
Podo-
foot
posterior
toward the back or dorsal
proximal
closest point of attachment
rhin-
nose
spino-
spine
superior
uppermost or above
-stomy
opening
thorac-
chest
-tomy
cut
uro-, -uria
urine
vas-
vessel
Abbreviations
There are many abbreviations related to working in the health and aged care
environment become familiar with some of these. The following tables
(insert table numbers) provide a list of common abbreviations, symbols and
acronyms as well as their meanings. This list is not exhaustive but shows
those most frequently used.
Commonly used abbreviations
Abbreviation
Meaning
abdo
abdomen
Ht
height
lab
laboratory
NAD
nil abnormalities detected
Neg or -ve
negative
obs
observations
Pos or +ve
positive
Wt
weight
Common symbols
Symbol
Meaning
♂
male
♀
female
#
fracture
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<
less than
>
more than
Δ
disease or disorder
.
/l
one
.
/ll
twice
.
/c
with
Px
treatment
Common acronyms
Acronym
Meaning
ADK
activities of daily living
BD
twice a day
BGL
blood glucose level
BKA
below knee amputation
BNO
bowels not opened
BO
bowels opened
BP
blood pressure
CCF
congestive cardiac failure
CVA
cerebral vascular accident
CXR
chest x-ray
DNR or
NFR
do not resuscitate or
not for resuscitation
ECG
electrocardiogram
EEG
electroencephalogram
GIT
gastrointestinal tract
HRS
hours
IDC
indwelling catheter
IV
intravenous
MI
mycardial infarcation
MS
multiple sclerosis
NBM
nil by mouth
PAC
pressure area care
PEG
percutaneous endoscopic gastrostomy
PRN
as required
PVD
peripheral vascular disease
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ROM
range of motion
SOB
shortness of breath
SPC
supra-pubic catheter
TDS
three times per day
THR
total hip replacement
TIA
transient ischaemic attack
TPR
temperature, pulse and respiration
UA
urinalysis
UTI
urinary tract infection
The main purpose of documentation is to successfully communicate
information, it is important that everyone can read and understand what is
written. Using abbreviations that not all workers are familiar with can lead
to the omission of care or incorrect care being given to an older person.
If unfamiliar abbreviations are found in the workplace documentation, the
acceptable abbreviations list should be checked. If the abbreviation does not
appear on the list, the supervisor should be contacted for further
clarification.
Apply a basic understanding of the
fundamental principles of maintaining a
healthy body
The human body is an extremely complex organism. The body is made up
of many different systems that work together to keep us healthy. All body
systems start from simple chemicals which combine to make the basic units
of life, cells.
Organisation of the body
The human body is organised into various levels that begin at the very small
and basic and come together to form the complete body whose different
parts work in unison. This can be seen as a kind of ‘ladder’ going from the
basic (simple chemicals, atoms) to the very complex.
At the simplest level, the body is comprised of atoms. As seen in the
flowchart following atoms combine to form molecules to form cells, to form
tissues, to form organs, to form body systems, to form the human body.
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From atoms to the human body
The human body is built from tiny atoms to major organ systems
Organisation of the body from chemical level to cellular level, to tissue level, to
organ level, to system level, to the human body
Cells
The basic unit of body structure is the cell. All cells need food, water, and
oxygen to live and function. As cells use or metabolise food and oxygen
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they give off carbon dioxide and other wastes. The cell is comprised of the
cell membrane, which is the outer covering; it encloses the cell and helps it
hold its shape.
The nucleus is the control centre; it directs the cell’s activities. Cytoplasm
surrounds the nucleus. Organelles are structures that are suspended in the
cytoplasm. The protoplasm refers to all structures, substances and water
within the cell.
Chromosomes are threadlike structures within the nucleus. Each cell has 46
chromosomes. Chromosomes contain genes, which determine our physical
and chemical makeup.
Features of cells include:

the cell is the most basic unit of life

there are cells that are organisms themselves, such as bacteria cells

there are cells that only function when part of a larger organism

in the body, there are brain cells, skin cells, liver cells, blood cells
and many more

all of the cells have unique functions and features.
Although cells may be very different and highly specialised, they all have
the same basic structure. They all have:

an outer covering called the membrane

a main substance called the cytoplasm

a control centre known as the nucleus

organelles dispersed within their cytoplasm.
The cell membrane protects the cell and regulates the passage of materials
into and out of the cell.
The nucleus is the control centre of the cell. DNA, which makes up the
genes, is found within the chromatin granules and within the nucleolus is the
RNA.
Organelles, which are structures found in the cytoplasm, are the:

mitochondria, the ‘powerhouse’ of the cell, function in cellular
metabolism and respiration

endoplasmic reticulum produces proteins and lipids and transports
these substances within the cell

lysosomes function in intracellular digestion and form the ‘selfdestruct’ system of the cell

golgi complex concentrates some secretions, adds carbohydrates to
some secretions and packages secretions for export from the cell
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
vacuoles are small cavities within the cell used to store secretions or
waste products

centrioles, cilia and flagella are composed of microtubules
o centrioles are contained in the centrosome and are involved
in mitosis (cell division)
o cilia aid in the movement of materials outside the cell. For
example, trapping of dust particles in the respiratory tract.
o flagella are important in the locomotion of sperm cells.
The functions of the cell include:
1. Respiration – all cells require oxygen to metabolise food.
2. Ingestion and assimilation – cells are able to select chemicals from
the surrounding fluid for their structure.
3. Growth and repair – cells can synthesise new cytoplasm so that
growth can occur and repair worn out parts.
4. Excretion – waste products are eliminated into surrounding tissue to
be transported by the blood for elimination via organs.
5. Irritability and activity – cells are able to respond to stimuli. For
example a stimulus causes a muscle to contract or relax.
6. Metabolism – cells are able to break down and use substances from
food as fuel.
7. Reproduction – cells reproduce by simple division but some cells
can never be replaced once destroyed. For example, central nervous
system cells.
Tissues
Groups of cells form tissues and there are four main types. The structure of
tissues reflects their function.
Types
Function
Example
Epithelial
Protection
Skin
Connective
Support
Bones
Muscular
Movement
Skeletal
Nervous
Communication
Brain
Epithelial tissue
This tissue covers the body surfaces and lines its cavities. Some specialise to
form glands.
The functions of epithelial tissue include:

protection
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
absorption

secretion

excretion

surface transport

reception of sensory information.
A gland is one or more epithelial cells specialised to produce and discharge
substances.
Endocrine glands secrete have no ducts and secrete hormones directly into
the bloodstream, for example pituitary gland.
Exocrine glands release their secretions through ducts, for example salivary
and sweat glands.
Connective tissue
This tissue joins other tissues of the body together, supports the body and
protects underlying organs.
Some main types are:

ordinary connective tissue — subcutaneous tissue and collagen

adipose tissue — stores fat

cartilage — protects joints and supports soft tissues

bone — rigid supporting tissue of the skeleton

blood — lymph and lymphoid tissue—produce blood cells
Muscular tissue

Muscle is composed of cells specialised to contract.

Skeletal muscle is striated (striped) and is under voluntary control.

Cardiac muscle is present only in the walls of the heart, is striated
and is controlled by involuntary nerve messages from the brain.

Smooth muscle, also involuntary, is responsible for movement of
food through the digestive tract, and changing the diameter of blood
vessels.
Nervous tissue
Nervous tissue forms the brain, spinal cord and the nerves. The basic cell is
called the neuron.
Specialised to receive stimuli and send impulses from one part of the body
to another.
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Organs
Groups of tissues come together to form organs. For example the heart is
made up of cardiac muscle and nervous tissues, held together with
connective tissues and lined with epithelium. Each organ has a specific
function.
Organ
Function
Heart
Circulation
Stomach
Digestion
Brain
Communication/coordination
Uterus
Reproduction
Body systems
Several organs working together form a system. For example the urinary
system is made up of the kidneys, bladder and ureters.
System
Organs
Cardiovascular
Heart, blood, vessels
Respiratory
Nose, pharynx, trachea, bronchus, bronchiole, lungs, alveoli
Musculoskeletal
Muscles, joints, bones
Integumentary
Skin
Nervous
Brain, spinal chord, nerves
Gastrointestinal/Digestive
Tongue, oesophagus, stomach, liver, pancreas, gall bladder,
small intestine, large intestine, rectum, anus
Urinary
Kidneys, ureters, bladder, urethra
Reproductive
Male: Testes, scrotum, vas deferens, seminal vesicle,
prostate, ejaculatory duct, urethra, penis, glans, perineum
Female: Ovaries, fallopian tubes, uterus, cervix, vagina,
labia, urethra, clitoris, perineum
Endocrine
Glands: pituitary, hypothalamus, pineal, parathyroid,
thyroid, adrenals, pancreas, gonads: ovaries ♀; testes ♂, and
their hormones.
Lymphatic/Immune
Lymph glands and vessels, lymph, lymphocytes, T and B
cells.
Internal cavities
The body has two (2) sets of internal cavities that provide different degrees
of protection to the organs that lie within them. These are the:
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1. Dorsal cavity is divided into the cranial cavity, containing the brain,
and the spinal cavity, containing the spinal cord. Organs in the dorsal
cavity coordinate the body’s functions via the nervous system.
2. Ventral cavity which comprises the thorax (chest) – this encases the
heart and the lungs and the abdominopelvic cavity which encases our
abdominal organs and those of our reproductive system. Organs in
the ventral cavity work to maintain a constant internal environment,
or homeostasis.
Body cavities
Diagram of body cavities including cranial thoracic, abdominal, spinal and pelvic
Body regions
The body is also divided into regions. Examples of these include the:

epigastric region — which lies below the bottom of the breastbone
and above the umbilicus (belly button)

inguinal region — which lies within the groin
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
cervical region — which lies at the back of the neck

gluteal region — which lies in the area of the buttocks.
Work with knowledge of the major
components of each body system and
their location in relationship to other
structures
There are 11 body systems, each performing specific tasks. They are:

cardiovascular system

respiratory system

musculoskeletal system

nervous system

sensory system

integumentary system

gastrointestinal system

urinary system

immune system

endocrine system

reproductive system.
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Systems overview
Diagram showing systems overview: cardiovascular system, respiratory system,
skeletal system, muscular system, nervous system, integumentary system,
gastrointestinal system, urinary system, lymphatic system, endocrine system,
reproductive system
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Cardiovascular system
The cardiovascular system is one of the major body systems. It transports
oxygen, carbon dioxide, waste products, nutrients and hormones to and from
various parts of the body.
The cardiovascular system is made up of the heart, the blood vessels
(arteries and veins and capillaries) and blood. The heart has major vessels
that return deoxygenated blood to the right side of the heart (travels back to
the heart from the body), and major vessels that carry oxygenated blood
away from the left side of the heart to all the parts of the body, including the
heart itself.
Heart
The heart is a hollow organ about the size of a fist and is composed of
special muscle tissue (cardiac muscle). It lies under the breast bone in the
centre of the cardiothoracic cavity. In the average lifetime the heart beats
250 million times and pumps 340 million litres of blood. The heart is a
sophisticated pump that is controlled by an electrical current that is initiated
in the brain.
Location of the heart and the major vessels that supply blood to the heart
Drawing showing superior and inferior vena cava, aorta, heart, lungs
The heart is divided into a left and right side by a muscular wall called the
septum and has four chambers.
Heart chambers and valves
The chambers of the heart include the:
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
right atrium which receives deoxygenated blood (low in oxygen)
from all over the body

right ventricle receives blood from the right atrium and sends it to
the lungs via the pulmonary artery to become oxygenated and get rid
of carbon dioxide

left atrium receives oxygenated blood from the lungs and sends it to
the left ventricle

left ventricle receives blood from the left atrium and sends it out to
the body via the aorta.
The heart wall consists of three layers—the endocardium is the inner lining,
the myocardium is the muscle layer and the pericardium is the outer
covering.
The chambers of the heart are separated by valves:

tricuspid valve is located between the right atrium and right ventricle

bicuspid (mitral) valve is located between the left atrium and left
ventricle

pulmonary valve is between the right ventricle and the pulmonary
artery

aortic valve is between the left ventricle and the aorta
The major vessels that carry blood to and from the heart are:

inferior vena cava conveys deoxygenated blood (blood low in
oxygen) from the lower extremities of the body to the heart

superior vena cava coveys deoxygenated blood from the upper
extremities of the body to the heart

aorta conveys oxygenated blood (blood high in oxygen) away from
the heart
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Structures of the heart
Illustration showing the position of the structures of the heart including the aorta,
ventricles, valves
Blood vessels
The cardiovascular system consists of arteries and veins and capillaries.
Arteries carry oxygenated blood to the cells of the body; veins carry
deoxygenated blood away from the cells.
Arteries
Arteries are tubes that carry oxygenated blood (high in oxygen) away from
the heart.
Arteries have thick, muscular, elastic walls. They branch off forming
arterioles with thinner walls that then become capillaries. Arteries carry
blood rich in oxygen and nutrients.
Blood that comes from a wound where there is damaged (due to action of
heart pumping) is bright red and spurts. The aorta is the largest artery and as
it leaves the heart it branches into smaller arteries, eventually they become
capillaries.
Veins
Veins carry deoxygenated blood (low in oxygen) from the cells back to the
heart where it is pumped to the lungs so that the blood can pick up more
oxygen. The veins have one-way valves that help move the blood toward the
heart.
Veins have thinner muscular walls. They carry blood back to the heart that
is low in oxygen and high in carbon dioxide, a waste product.
Blood that comes from a wound where a vein is damaged (due to action of
heart pumping) is dark red (deoxygenated) and oozes or runs out (does not
spurt).
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Arteries
Veins
Venous and arterial circulation
Diagrams of veins and arteries throughout body
Capillaries
Capillaries are very small vessels that surround the cells of the body and
facilitate the movement of oxygen and nutrients into the cells and carbon
dioxide and waste products away from the cells.
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Capillaries
Diagram showing distribution of capillaries around veins and arteries
Blood
Blood is made up of a liquid (plasma) and cells. Blood is connective tissue,
a red body fluid made up of liquid (plasma) and cells. The body contains
five to six litres of blood. Fifty-five percent of the blood is plasma.
Drawing of a tube with plasma in half of the tube, a small bit of white blood cells
and platelets and the rest red blood cells
Components of blood
Plasma
Plasma is a straw coloured watery fluid in which the blood cells are
suspended.
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It contains antibodies (gamma globulin) and antitoxins, plasma proteins,
mineral salts, nutrients, waste products such as urea and creatinine, gases
such as oxygen and carbon dioxide, hormones and enzymes.
The blood cells float in the plasma. They are produced in the bone marrow
and lymphatic tissues of the body.
The bone marrow, liver and spleen destroy worn-out blood cells.
Blood cells
There are three types of blood cells.
1. Erythrocytes or red blood cells (RBC)—carry most of the oxygen
and small amounts of carbon dioxide. Haemoglobin carries the
oxygen molecule and gives blood its colour. There are
approximately 5 million RBC per cubic millimetre of blood and the
average life span is 100—120 days.
Red blood cells
Red blood cells
2. Leucocytes or white blood cells (WBC)—help fight infection as they
can attack micro-organisms. There are 7,000—8,000 WBC per cubic
millimetre.
White blood cells
White blood cells
3. Thrombocytes (platelets) — are parts of cells which plug small leaks
in the walls of blood vessels and initiate blood clotting. There are
200,000 to 400,000 per cubic millimetre.
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Platelets
Diagram of platelets
For more information on blood and blood products visit the Australian Red
Cross Blood Service website at http://www.arcbs.redcross.org.au/
Flow of blood through the heart
The correct term for contraction of the heart is systole. This is followed by
relaxation of the heart called diastole. One systole and diastole form the
cardiac cycle. A cardiac cycle takes only 0.8 seconds and during this time
the following events occur.
First, the upper chambers, or atria, of the heart relax and fill with blood as
the lower ventricles contract, forcing out blood through the aorta and
pulmonary arteries. Next the ventricles relax, allowing blood to flow into
them from the contracting upper chambers. Then the cycle is repeated; this
happens approximately 70 to 80 times per minute.
The rate and rhythm of the heart is regulated by the conduction system that
is made up of specialised neuromuscular tissue that sends out impulses. The
impulses begin at the Sino-Atrial (SA) node in the right atrium and spread
across the two atria. The atria then contract and the impulses from the S-A
node reach the Atrio-Ventricular (AV) node in the right atrium. Messages
from the A-V node then travel down the Bundle of His in the septum and
continue through the Purkinje fibres to the walls of the ventricles.
An electrocardiogram, or ECG, is a diagnostic test that records the electrical
impulses of the heart.
The blood flows around the body continuously due to the regular beat of the
heart. Beginning at cells, the passage of blood is as follows:
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Diagram of the flow of blood through arteries and veins
Diagram of the flow of blood through arteries and veins
As seen in the following diagram blood cell arrives deoxygenated into the
right atrium and passes into the right ventricle through the tricuspid valve.
The blood cell leaves the heart through the pulmonary valve into the
pulmonary artery where it travels to the lungs to be oxygenated.
Blood cells enter right atrium and pass into right ventricle, and leave through the
pulmonary artery where it travels to the lung
Diagram showing entry of blood cells into right atrium and passage into right
ventricle, and leaving through the pulmonary artery where it travels to the lung
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The oxygenated blood cell returns to the heart through the pulmonary vein
into the left atrium. The blood cell moves into the left ventricle through the
mitral valve.
The blood cell then moves from the heart into the body through the aorta
passing through the aortic valve.
Oxygenated blood cells return to the heart through the pulmonary vein into the left
atrium and then move from the heart into the body through the aorta
Diagram showing oxygenated blood cells return to the heart through the pulmonary
vein into the left atrium and then moving from the heart into the body through the
aorta
Respiratory system
The respiratory system is composed of various structures and organs that
ensure that the body is able to maintain its internal environment through the
exchange of air between the lungs and the atmosphere. In order to survive
the body needs a constant supply of oxygen, which it obtains from the air.
The body also needs to dispose of carbon dioxide, made as a waste product
from the process of cell metabolism. The ingestion of oxygen and the
discarding of carbon dioxide occurs through the process of respiration or
breathing.
Structure of respiratory system
The respiratory system is comprised of the:

nose
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
nasopharynx

mouth

sinuses

larynx

trachea

bronchi

lungs

alveoli
The respiratory system
Diagram showing labelled parts of the respiratory system
The respiratory system contains the upper and the lower respiratory tracts.
The upper respiratory tract contains the respiratory organs located outside
the chest cavity: the nose and the nasal cavities, pharynx, larynx and upper
trachea.
The lower respiratory tract consists of organs located in the chest cavity: the
lower trachea, bronchi, bronchioles, alveoli and the lungs. The lungs have
lobes 3 lobes in right lung and 2 lobes in left to accommodate the heart.
The lower parts of the bronchi, the bronchioles and alveoli, are all located in
the lungs. The alveoli are the point at which gas exchange takes place.
The pleura are a membrane that covers the lungs.
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The muscles that form the chest cavity are also part of the lower respiratory
tract. The respiratory centre in the brain, which is located in the medulla
oblongata, regulates breathing.
Function of respiratory system
The function of the respiratory system is to supply oxygen and to remove
carbon dioxide from cells.
Oxygen is needed by cells to produce heat and energy. In using oxygen, the
cells produce carbon dioxide as waste.
Inhaled air is moistened and warmed as it passes through the upper
respiratory tract—the nose, the pharynx and the larynx. The clean air passes
on through the lower respiratory tract—the trachea, bronchi, lungs and the
alveoli where the exchange of gases takes place.
Respiration
Respiration involves the passage of air in and out of the lungs.
Air passes from nose to the pharynx to the larynx to the trachea to the left
and right bronchus to the bronchioles to the alveoli (where a gas exchange
takes place and oxygen and carbon dioxide are exchanged in the pulmonary
capillaries)
Air enters the body via the nasal passages, where it is warmed, moistened
and filtered. Air then passes down through the pharynx and into the larynx
and trachea. The air continues into the right and left bronchi and then into
the lungs. In the lungs the bronchi then branch into smaller bronchioles, that
each has air sacs called alveoli, attached to them. The exchange of oxygen
and carbon dioxide takes place at this level, between the alveoli and the
blood capillaries. Through this process oxygen enters the bloodstream and
can be transported around the body.
Musculoskeletal system
The musculoskeletal system consists of the bones, muscles, ligaments and
tendons
The skeletal system
The skeletal system is comprised of bones and joints and provides the basic
supporting structure of the body. It consists of the joined framework of
bones called the skeleton.
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Major bone structures of the body
Diagram of the major bone structures of the body
Structure of musculoskeletal system
Bones
There are 206 bones in the human body. Bone is a dry, dense tissue
composed of a calcium-phosphorus mineral and organic matter and water.
Bone is covered with a living membrane called the periosteum. The
periosteum contains bone-forming cells, the osteoblasts.
The centre of bone contains marrow where blood vessels, fat cells and tissue
for manufacturing blood cells are all found.
There are four main shapes of bones:

flat, eg ribs

irregular, eg vertebrae

short, eg hand (carpals)

long, eg upper arm (humerus).
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Joints
A joint is an area where two or more bones are in contact with each other.
Joints allow movement. The bones forming the joint are held together by
ligaments.
There are three types of joints:
1. fibrous or immovable eg skull
2. cartilaginous or slightly moveable eg vertebrae
3. synovial or freely movable:

ball and socket eg hip

hinge eg elbow.

gliding eg carpals at wrist

pivot eg radius and ulna.
There are certain terms that are used to describe the movement of bones:

abduction—movement away from the body

adduction—movement towards the body

flexion—bending a limb towards the body

extension—extending a limb away from the body

rotation—movement around a central point.
You have learnt the names of the various joints of the body, but there are
also words that describe the various directions in which limbs move.
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Movement of the joints
Diagrams showing movements of the joints
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The muscular system
The muscular system allows us to move and you will need to learn about the
muscles of the body in order to understand how this system contributes to
the overall design of the human body. The human body is composed of over
500 muscles working together to facilitate movement.
It is very important to understand the muscular system and how it works in
conjunction with the skeletal system to allow us to move and maintain our
posture.
The major function of the muscular system is to produce movements of the
body, to maintain the position of the body against the force of gravity and to
produce movements of structures inside the body.
Structure of musculoskeletal system
Tendons attach muscle to bone.
There are 3 types of muscles:
1
skeletal (voluntary) muscles are attached to bone by tendons
2
smooth (involuntary) muscles control the actions of our gut and
blood vessels
3
cardiac muscle in the heart.
Muscles contract (shorten) and relax in response to chemicals and the
stimulation of a motor nerve. Movement occurs when muscles contract or
shorten, pulling the bones with them. Muscles work in pairs; when one
shortens, the corresponding muscle lengthens. Some examples of muscles
are the triceps, deltoid and the biceps in the upper arm and the gluteal
muscle, the hamstrings and the quadriceps in the buttocks and the top of the
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Major muscles group — anterior view
Diagram of major muscles group — anterior view
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Major muscles group — posterior view
Diagram of major muscles group — posterior view
Function of musculoskeletal system
The function of the musculoskeletal system is to:

protect and support the internal structures and organs of the body

allow movement

give shape to the body

produce blood cells

store calcium and phosphorus.
Nervous system
The nervous system is responsible for coordinating all of the body’s
activities. It controls not only the maintenance of normal functions but also
the body’s ability to cope with emergency situations.
Function of nervous system
The nervous system has three general functions: a sensory function, an
interpretative function and a motor function.
1. Sensory nerves gather information from inside the body and the
outside environment. The nerves then carry the information to
central nervous system (CNS).
2. Sensory information brought to the CNS is processed and
interpreted.
3. Motor nerves convey information from the CNS to the muscles and
the glands of the body.
Structure of nervous system
The nervous system is divided into two parts:
1. the central nervous system consisting of the brain and spinal cord.
These structures are protected by bone and cushioned from injury by
the cerebrospinal fluid (CSF)
2. the peripheral system which connects the central nervous system to
the rest of the body.
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The central nervous system
Diagram of central nervous system
Central nervous system
These structures are protected by bone and cushioned from injury by the
cerebrospinal fluid (CSF).
Brain
The brain is a mass of soft nerve tissue, which is encapsulated within the
skull. It is made up of grey matter, mainly nerve cell bodies, and white
matter which are the cell processes. The grey matter is found at the
periphery of the brain and in the centre of the spinal cord. White matter is
found deep within the brain, at the periphery of the spinal cord and as the
peripheral nerves.
The brain is divided into:

Cerebrum – the largest part of the brain. It is the centre for thought
and intelligence. It is divided into right and left hemispheres. The
right controls movement and activities on the left side of the body.
The left controls the right side of the body. Within the cerebrum are
areas for speech, hearing, smell, sight, memory, learning and motor
and sensory areas.

Cerebral cortex – the outside of the cerebrum. Its function is
learning, reasoning, language and memory.

Cerebellum – lies below the cerebrum at the back of the skull. Its
functions are to control voluntary muscles, balance and muscle tone.
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
Medulla – controls heart rate, breathing, swallowing, coughing and
vomiting. Together with the pons and the midbrain, the medulla
forms the brainstem that connects the cerebrum to the spinal chord.
The different sections of the brain
Diagram of different sections of the brain
Lobes of the brain
It is important to have an understanding of how the brain functions and
which parts control our functioning and behaviour. For example, when a
casualty suffers from a stroke, the part of the brain that is affected controls
function. If it is the frontal lobe, speech, thought and movement may be
affected.
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The different quadrants of the brain
Diagram of different quadrants of the brain
The spinal cord
The spinal cord is about 45 cms long, extending from the medulla down to
the second lumbar vertebrae. It acts as a message pathway between the brain
and the rest of the body. Nerves conveying impulses from the brain,
otherwise known as efferent or motor nerves, travel through the spinal cord
down to the various organs of the body. When the impulses reach the
appropriate level they leave the cord to travel to the’ target organ.
Sensory or afferent nerve impulses also use the spinal cord to travel from
various parts of the body up to the brain.
Parts of the spinal chord
Diagram of the spinal chord system
The peripheral system connects the central nervous system to the rest of the
body. The main divisions of the Peripheral Nervous System are:

The autonomic nervous system – which controls the automatic
functions of the body: the heart, smooth muscle (organs) and glands.
It is divided into the ‘fight-or-flight’ system and the ‘resting and
digesting’ system.

The somatic nervous system –which allows us to consciously or
voluntarily control our skeletal muscles. The somatic system
contains 12 cranial nerves and 31 spinal nerves.

Nerves –which are made up of special cells called neurons. Neurons
are comprised of a dendrite, a cell body and an axon. Impulses travel
to the dendrite into the cell body and then onto the axon. A special
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sheath called myelin, which increases the conductivity of the neuron,
covers some nerves.
As messages travel from one neuron to the next they move across a synapse.
At each synapse there is a chemical called a neurotransmitter. At various
parts of the body specific neurotransmitters facilitate communication, for
example dopamine (motor function), serotonin (mood) and endorphins
(painkillers). Sensory neurons carry messages from a receptor to the brain.
The brain then interprets the message. Motor neurons then send the message
to an affector in muscles and glands.
Receptor (sensory organ) sends a signal to the sensory neuron which sends a
signal to the brain/spinal chord which sends a signal to the motor neuron
which sends a signal to the affector (muscle/gland).
The neurone
The basic unit of the nervous system is a specialised cell called the neurone.
These nerve cells make up a massive network of specialised cells that
transmit messages, very rapidly, from one part of the body to another.
Information is transmitted via electrical impulses.
The neurone is comprised of a nerve cell and its adjoining processes called
an axon and dendrites. Every nerve cell has one or more processes attached
to it. Electrical impulses enter the neurone via the dendrites and leave via
the axon. The space between the axon of one cell and the dendrites of
another is called a synapse. Specialised chemicals called neurotransmitters
help conduct impulses through the synapse onto the next cell.
Structures of the neurone
Diagram showing structures of the neurone
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Sensory system
Our sensory system provides information about our internal and external
environment and assists in communication. We have both special senses and
general senses. The special senses are localised in a specific area of the
body, whereas the general senses found throughout the body. Special senses
include vision, hearing, equilibrium, smell and taste. General senses include
pressure, temperature, pain, touch and a sense of position.
Taste – the tongue
The receptors for taste lie in the tongue and are able to identify four types of
taste: sweet, salty, bitter, sour. These taste ‘pores’ are found on papillae on
the tongue and when they are stimulated by chemicals in the saliva they
send impulses to the brain to be interpreted by a specific area of the cortex.
Smell – the nose
The receptors for smell are located in the superior aspect of each nasal
cavity. Sniffing helps bring more air (containing odours) over the olfactory
mucosa. Olfactory neural pathways are closely linked to the limbic system:
odours can vividly recall memories and arouse an emotional response.
Note: Taste and appreciation of foods is influenced by the sense of smell
and the temperature and texture of foods.
Hearing and balance – the ear
The ear is divided into three main areas: the external ear; the middle ear; and
the inner ear. The outer and middle ear is involved in hearing only. The
inner ear functions in both balance and hearing. The external ear is
composed of the pinna and the external auditory canal. In the walls of the
external auditory canal are glands that secrete earwax or cerumen.
Sound waves entering the external auditory canal eventually hit the eardrum
or the tympanic membrane and cause it to vibrate. The eardrum separates
the outer and the middle ear. The middle ear is a small space containing the
eustachian tube and three small bones called the ossicles. The eustachian
tube connects the middle ear and the throat. The ossicles amplify sound
received from the eardrum and transmit it to the inner ear. The inner ear
consists of the semi-circular canals and the cochlea, which contains fluid. In
the cochlea, fluid carries sound waves received from the middle ear to
the auditory nerve. The auditory nerve carries the message to the brain. The
semi-circular canals are involved in balance. They sense the head’s position
and changes in position and send messages to the brain (Herlihy et al 2000).
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The ear
Diagram showing parts of outer (external), middle and inner ear
Vision – the eye
The eye is a hollow sphere. The accessory structures of the eye include the
extrinsic eye muscles, the tear (lacrimal) glands and ducts, the eyelids, the
eyelashes and the conjunctiva. Light rays from a distant object are nearly
parallel as they reach the eye and can be focused without change to the
shape of the lens (convex). Diverging light rays from close objects require
that the lens bulge more to focus the image more sharply on the retina. This
ability of the eye to focus specifically for close objects is called
accommodation. The image formed on the retina as a result of the lightbending activity of the lens is a real image — that is, it is reversed, upsidedown and smaller than the object.
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The eye
Diagram showing interior and exterior view of the eye
Integumentary (skin) system
The skin (also known as the integumentary system) covers the body and is
the body’s largest organ. Different parts of the body have a different
thickness of skin. For example, the skin on the soles of your feet is thicker
than the skin on your face.
Structure of integumentary system
The skin is made up of three layers – two of these are skin layers and one is
composed of fatty tissue. The two skin layers are the epidermis and dermis
(see figure below)
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Structure of the skin
Diagram showing structure of the skin
Function of integumentary system
The skin functions as a protective covering—the skin protects everything
underneath it and plays a major role in homeostasis. Another function is in
maintaining the internal body temperature. It is also a major means of
communication through touch and sensation.
Protection
The skin surface provides a tight, waterproof barrier and prevents
potentially harmful organisms from entering the body. It also protects
internal organs from external injury. The skin helps fight infection and
protects against infection as long as it remains intact. The waterproof quality
of the outer layer prevents excessive water absorption and abnormal water
loss from the body, reducing the risk of dehydration.
Temperature regulation
The skin plays a major role in maintaining the internal body temperature
because blood vessels can dilate or constrict. When the body temperature
starts to rise, the blood vessels respond by dilating and increasing blood
flow to the body surface, bringing inner heat to the surface. The sweat
glands secrete fluid onto the skin, and it is the evaporation of this fluid that
cools the body. When the body temperature starts to falls, the blood vessels
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respond by constricting and decreasing blood flow to the body surface,
reducing heat loss through the skin. The sweat glands inhibit the release of
fluid, and evaporation from the skin is reduced to help the body retain heat.
Body temperature
Body temperature is the balance between the amount of heat produced and
the amount of heat lost by the body. Body temperature remains fairly stable.
Factors affecting body temperature are age, weather, exercise, emotions,
stress, pregnancy, the menstrual cycle and illness.
The normal body temperature range for an adult is between 36.0. – 37.2 ºC.
A subnormal temperature reading would be considered less than 36 ºC if
measured at the oral or axillary site.
Sensory input
The skin contains nerve endings that are sensitive to touch, pressure,
vibration, pain and temperature. These nerve endings respond to each of
these sensations and send messages to the brain to alert us. For example, if
you touch a hot object with your hand, your immediate and automatic
reaction will be to remove your hand from the heat source to avoid injury.
Fluid and electrolyte balance
The skin helps regulate the fluid and electrolyte balance by eliminating
water and small amounts of salts through the sweat glands.
The skin, in the presence of sunlight, begins the process of forming vitamin
D, a substance required to absorb calcium and phosphates from food. It is
the cells in the epidermis (melanocytes) that are responsible for this process.
Gastrointestinal (digestive) system
The human body needs energy, to be able to perform all the vital functions
that are part of living. The gastrointestinal or digestive system converts the
food that we eat into a form that can be processed and used as energy for all
the activities carried out by the body. The type of foods that we ingest has
an effect on the way that it is processed in the body and the amount of
energy that is produced.
As food passes through the digestive tract it is broken down, both physically
and chemically into a form that can be absorbed into the bloodstream and
used by the body for energy. Those particles that are unable to be digested
are excreted in the form of faeces.
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Gastrointestinal system
Graphic showing the position of the mouth, liver, gall bladder, small intestines,
stomach, pancreas and large intestines
Structure of gastrointestinal system
There are two main groups of organs and these are:
1. Gastrointestinal tract (GIT) (also called the alimentary canal)
extends from the mouth to the anus.
2. Accessory structures which assist in the mechanical and chemical
breakdown of food—these include teeth, tongue and glands lining
the GIT.
Mouth
The process of digestion begins in the mouth where food is chewed until it
reaches a consistency whereby it can be swallowed. The following
accessory structures aid this early stage of digestion:

Tongue – a muscle that is covered by tastebuds. It assists the process
of chewing and manoeuvres food to a position where it can be
swallowed easily.

Salivary glands – begin the process of chemical digestion through
the secretion of the enzyme, salivary amylase. This enzyme begins
the process of breaking down carbohydrates. Saliva also moistens
food which helps it to be swallowed more easily.
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
Teeth – break food down mechanically into smaller particles that
may be ingested more easily.

Pharynx – allows the passage of both food and air.

Oesophagus – tube that leads to the stomach.
Oesophagus
The oesophagus is the tube or gullet connecting the mouth to the stomach. It
lies in front of the vertebral column and behind the trachea (breathing tube)
and heart.
Stomach
Food remains in the stomach for 3 to 4 hours. During this time it is further
broken down by the muscular churning action of the stomach. Powerful
gastric juices are also secreted by the cells of the stomach, contributing to
chemical digestion. The food ends up in a semi-liquid form that is called
chyme.
Intestines
Digested material is moved through the intestine via a process of wavelike
muscular contractions called peristalsis. The process of digestion is
completed in the small intestine. At this stage the nutrients that the body
needs are absorbed through the walls of the small intestine.
The waste material then moves into the large intestine where water is
reabsorbed; thereby changing it into a more solid form, ready to be excreted
through the rectum.
Liver
The liver is a large gland that is divided into four lobes. It carries out many
vital metabolic functions such as:

manufacturing bile which breaks down fats

helping to maintain normal blood glucose levels

producing the blood proteins, prothrombin and fibrinogen which
have a role in blood clotting

storing iron derived from food or the by-product of the breakdown of
worn out red blood cells

storing vitamins A, D, E & K, that have been extracted from food
ingested

heat production due to the high amount of metabolic activity; the
liver is the main heat procuring organ of the body.
Gallbladder
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The gallbladder concentrates and stores bile that is produced in the liver. It
then releases the bile when it is needed for digestion after a fatty meal.
Pancreas
The pancreas is what is called both an endocrine and exocrine gland. It
produces pancreatic juices, containing enzymes, which play an important
role in the chemical digestion of food. The pancreas also produces the
hormones insulin and glucagon directly into the bloodstream, which is
termed an endocrine function.
Function of gastrointestinal system
The function of the gastrointestinal system is to break down food
mechanically and chemically so it can be absorbed into the bloodstream and
then used by all tissues and cells. This process is called digestion and
absorption.
Every cell in the body requires energy in order to carry out its normal
function; however the food we swallow is too large to enter the cells, so it
needs to be broken down to provide this energy. Another function of the
gastrointestinal system is to remove solid waste products from the body.
This process is called elimination.
The gastrointestinal system performs the following vital activities:

Ingestion which involves the taking in of food

Digestion which may take two forms:
o mechanical breakdown of food by chewing and the action of
muscles within the digestive tract.
o chemical breakdown of food by enzymes produced at various
stages of the digestive tract.
Absorption is where substances pass through the walls of parts of the
digestive tract into the bloodstream. 90% of the absorption of all nutrients
takes place in the small intestine. The other 10% take place in the stomach
and large intestines.
Elimination is the process by which undigested foods leave the body.
Digestion is controlled by the autonomic nervous system. Food moves along
the gastrointestinal system by a wave like motion called peristalsis that
breaks down the food mechanically. Food is also broken down chemically
by the action of enzymes and bacteria.
In the duodenum, food is acted upon by bile that is secreted by the gall
bladder, juices from the pancreas and secretions from the wall of the
duodenum. Fats are changed to fatty acids and glycerol, carbohydrates to
simple sugars and proteins to amino acids.
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Most of the absorption of nutrients takes place in the ileum through small
projections called villi.
Any undigested food and water moves into the colon. Movement is slow in
this section and it is anywhere from 16-24 hours before waste is evacuated.
This evacuation is a reflex action and is called defecation. It occurs as the
rectal sphincter responds to a filling of the colon and can be voluntarily
inhibited by keeping the external sphincter contracted.
Urinary system
Wastes are removed from the body through 4 body systems, respiratory,
gastrointestinal (digestive), integumentary (skin) as well as the urinary
system. We will explore how the urinary system removes wastes from the
body.
Structure of urinary system
The urinary system comprises the kidneys, bladder, ureters and urethra.
Male urinary system
Diagram showing structure of male urinary system
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Female urinary system
Diagram showing structure of female urinary system
Kidneys
One of a pair of organs found in the abdominal cavity. Located against the
back muscles on either side of the spine.
Ureters
Two tubes that run from the kidney to the bladder. Urine is conveyed
through the ureters by peristalsis and gravity.
Urinary bladder
The bladder is a hollow sac situated towards the front of the lower part of
the abdomen. The bladder stores urine.
Urethra
Urine is conveyed from the bladder through the urethra. In the female the
urethra is about 10cms long; in the male the urethra is about 20cms long and
also conveys semen. The opening at the end of the urethra is called the
urinary meatus.
The nephron
The nephron is the basic working unit of the kidney. Blood enters the
nephron under pressure and passes through the structures of the nephron to
be filtered. Most of the water and many substances that are needed by the
body are returned to the circulation. The kidneys produce 1-1.5 litres of
urine on average per 24 hrs. Many factors effect the production of urine.
These include age, illness, the amount of and type of fluids ingested, the
amount of salt in the diet, caffeine, alcohol and medications.
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Function of urinary system
The functions of the urinary system are to:

filter and remove waste products from the blood

maintain water balance within the body
 play a part in red blood cell formation.
 assists in the regulation of blood pressure.
Excretion of urine
Urination (also called ‘voiding’ or ‘micturition’) is the process of emptying
the bladder. As the bladder fills with urine, nerve impulses carry the
message to the spinal chord that the bladder is filling. The spinal chord then
sends a message back to the bladder via the motor nerves causing the
bladder to contract and the sphincter to relax. This is a ‘reflex’ that gives
rise to the urge to urinate.
Reproductive system
The reproductive system does not become active until puberty, when organs
mature in response to hormonal activity. The structures of the male and
female reproductive systems are different. These differences allow for the
process of reproduction.
Female reproductive system
The main features of the internal organs of the female reproductive system
are:
Vagina
The vagina extends from the vulva to where it opens to form the vaginal
opening.
Functions of female reproductive system
The main functions of the female reproductive system are:
 provides a passageway for the foetus to be expelled from the uterus
 receives the penis during coitus
 allows discharge of menstrual flow.
Uterus
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The uterus is a hollow pear-shaped muscular organ and it consists of a
fundus, body and cervix. The layers are the:
 perimetrium
 myometrium
 endometrium.
The functions of uterus are to:
 receives fertilised ovum (embeds in endometrium) or sheds
superficial layer if fertilisation does not take place at menstruation.
 contains the foetus during pregnancy
 expels the foetus at the end of pregnancy.
Fallopian tubes
The uterine tubes arise from the uterus and fan out to a trumpet-like shape
called fimbriae
The functions of the fallopian tubes are to transport the ovum from the
ovary to the uterus by means of peristalsis with the aid of ciliated cells in the
lining. Fertilisation takes place in the distal third of the uterine tube.
Ovaries
The ovaries are two almond shaped organs, each are located either side of
the uterus.
The functions of ovaries are to:

produce ova

produces hormone oestrogen and progesterone, which begins a
puberty.
Breasts
The breasts are mammary glands which in females increase in size a puberty
due to hormonal changes. When a woman gives birth to a baby the breasts
produce milk to nourish the newborn.
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Female reproductive system
Diagram showing female reproductive system
The menstrual cycle
The cycle of changes in the uterus in preparation for pregnancy. Between
puberty and menopause, the lining of the uterus goes through a 28-day cycle
of growth and discharge. Menstruation occurs if fertilisation does not take
place and the tissue lining the uterus that has been prepared for a fertilised
ovum is unused. This lining passes out through the vagina as menstruation.
Male reproductive system
The main features of the external and internal organs of the male
reproductive system are:
Penis
The penis conveys urine and seminal fluid to outside the body through the
urethra. It is the organ of coitus (sexual intercourse). The foreskin is
retractable sheath of skin covering the glans penis.
Scrotum
The scrotum is a skin pouch that encloses and protects the testes. It hangs
external to the body to maintain temperature control for the testes, which is
essential for sperm survival.
Testes
The testes are two egg-shaped organs containing sperm. They also produce
and secrete male sex hormones (testosterone). Testosterone production
begins at puberty.
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Epididymis and vas deferens
The Epididymis is a six-metre coiled tube that stores, transports and matures
sperm. The vas deferens is a duct that transfers the sperm to the urethra.
Ejaculatory ducts
The ejaculatory ducts receive sperm and additives to produce seminal fluid.
Prostate Gland
The prostate gland is the size of a walnut and surrounds the urethra. It
secretes an alkaline fluid that helps neutralise acidic seminal fluid and
enhances motility of sperm.
Urethra
A tube that serves as a dual purpose of conveying urine from the body and
semen.
Male reproductive system
Diagram showing male reproductive system
Functions of male reproductive system
The main functions of the male reproductive system are:
 testes (or testicles) which make the male sex hormone and contain
spem cells
 the tube structure on the outside of the mane body is the penius
through which spem cells pass from the urethra
 the prostate and seminal vesicles inside the lower abdomen produce
fluid for the sperm cells – the fluid and perm cells are called semen.
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Endocrine system
The endocrine system is a system of ductless glands that secrete chemicals
called hormones. Each hormone has a specific function, which may include
counteracting the effects of another hormone. The endocrine system works
side by side with the nervous system, assisting with growth, metabolism,
immunity and reproduction.
Hormones are secreted by endocrine glands directly into the bloodstream.
Hormones regulate growth, blood sugar, metabolism, reproduction as well
as various other functions such as sleep.
The body contains many different types of hormones that are designed to
regulate the body’s activities. Each hormone is specialised to target certain
types of cells, like a lock and key. The hormone will only work if it comes
into contact with the target cells. Hormone levels circulating in the body are
adjusted through a feedback to the glands.
Major glands of the endocrine system are the pituitary (master gland),
thyroid, parathyroid, adrenal, pancreas, ovaries and testes, thymus and
pineal glands
Endocrine system
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Diagram of endocrine system
Hormones
Hormones are chemical substances secreted by endocrine glands directly
into the blood. Hormones are classified as proteins and steroids. Hormones
are aimed at the ‘receptors’ of target organs. These receptors are located on
the outer surface of the cells of those organs. Hormone secretion is
controlled by three mechanisms: negative feedback, biorhythms and the
central nervous system.
Glands
Glands are located throughout the body.
The pituitary gland is the master gland and is located in the brain behind
the eyes at the base of the frontal lobe. It is divided into two parts—the
anterior and the posterior pituitary. Each part secretes specific hormones
that affect the action of other glands in the body.
The hypothalamus lies above the pituitary. It releases hormones that either
stimulate or inhibit the release of hormones by the anterior pituitary. The
pineal gland is located near the hypothalamus and houses our biologic clock.
The thyroid gland lies in the neck near the ‘Adams Apple’. It produces a
hormone that regulates growth and general metabolism.
The thymus lies in the chest above the xiphoid process and gets smaller
after puberty, but plays a part in the body’s immune system.
The parathyroids lie within the thyroid capsule. They produce a hormone
that regulates, along with one of the hormones of the thyroid gland, the level
of phosphorus and calcium in the blood. Calcium is important for many
functions of the body, such as muscle contraction and conduction of nerve
impulses.
The pancreas produces insulin and glucagon, which help regulate blood
glucose levels. Insulin acts to lower blood sugar level and glucagon acts to
raise blood sugar level.
The adrenal glands lie on top of the kidneys and secrete hormones that
help the body grow and adapt to stress.
The ovaries in the female secrete oestrogen and progesterone. The rise and
fall of these hormones determine the menstrual cycle and are important in
causing the release of the ovum (egg) and in the maintenance of pregnancy.
They are also responsible for the development of secondary sex
characteristics.
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The testes in the male produce testosterone, which causes the production of
sperm. Testosterone is also responsible for the development of secondary
sex characteristics.
Summary of glands and their hormones
GLAND
FUNCTION
Adrenal
Regulates salt and water in the blood assists body in coping with stress.
Pancreas
Regulates blood glucose levels.
Ovaries
Affect the formation of the ova and the development of the female sex
characteristics.
Parathyroid
Regulates the metabolism of calcium and phosphates.
Pituitary
Master gland.
Testes
Affect the formation of sperm and development of male sex
characteristics
Thymus
Aids in the formation of lymphocytes.
Thyroid
Controls rate of the body’s metabolism and influences growth and
development.
Lymphatic and immune system
The lymphatic system is a collection of organs (spleen, thymus, tonsils and
intestine), capillaries, lymph vessels, ducts and nodes which drain excess
fluid from the body, assists with fat absorption and helps the body defend
itself against disease.
Structure of the lymphatic system
The lymphatic system is comprised of
 lymphatic capillaries
 lymphatic vessels
 lymphatic nodes
 lymphatic tissue
 lymphatic ducts.
Lymph nodes are found in the axilla (under the arm), in the neck and in the
groin. Lymphatic tissue is found in the spleen, the tonsils and the thymus. It
is in the lymphatic tissue the lymphocytes are formed.
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The lymphatic system
Diagram of lymphatic system
Function of the lymphatic system
The lymphatic system is closely connected to the circulatory system. It
consists of an additional set of vessels. These lymphatic vessels return
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excess fluid (lymph) from the tissues to the blood. There are thousands of
lymph nodes clustered along these lymphatic vessels. These lymph nodes
help protect the body from disease by removing foreign material, such as
bacteria, virus as well as cancer cells.
The function of the lymphatic system is to:

remove foreign substances and waste products from blood and lymph,
eg dead cells, bacteria, viruses, and cancer cells

fight disease and to maintains the balance of fluid in the
tissues.
Working together with the lymphatic system is the immune system. The
immune system is a complex set of defences that guard the body against
harmful micro-organisms. The body has three key defence mechanisms to
protect against disease, and these are called first-line, second-line and thirdline defences.
Structure of the immune system
Immunity is best understood as lines of defence against invaders.
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The body’s lines of defence
Diagram of body’s lines of defence
The first line of defence is the body’s barriers, which include mechanical
barriers, chemical barriers and reflex actions

Mechanical barriers, for example, intact skin and mucous membrane,
protect the body against invading micro-organisms.

Chemical barriers. For example, saliva, tears, sweat, mucus and stomach
acid, help to destroy micro-organisms.

Reflexes, for example, coughing, sneezing, blinking and vomiting help
stop micro-organisms entering the body.
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The second line of defence is the body’s response to the invading microorganism. These response include the actions of phagocytosis,
inflammation, fever, protective proteins and natural killer cells.

Inflammation is the way the body responds to injury. Blood vessels
around the injury dilate, promoting blood flow to the area. This brings
phagocytes

Fever, a rise in the body’s temperature, helps to speed up repair of
tissues

Protective proteins aid in the inflammatory response by binding to the
invading micro- organism to prevent the spread of infection.

Natural killer cells (lymphocytes) directly attack invading microorganisms.

Phagocytosis means that white blood cells such as phagocytes ingest
invading micro-organisms and destroy them.
The third line of defence is the action of lymphocytes: T cells, B cells and
antibodies. They act directly on the invading micro-organism and provide
immunity against those that enter the body and are recognised as being
foreign.
Types of immunity
Immunity can be describes as the ability of the body to defend itself against
disease. There are two main types of immunity: inborn (natural) and
acquired (active).
Immunity can be either natural or active. Natural immunity is an
individual’s ability to ward off pathogens and is influenced by the person’s
state of health, their nutritional status and their emotional response to stress.
Active immunity occurs as the body builds up a resistance to pathogens that
have been introduced through exposure or by immunisation.
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Types of immunity
Diagram showing types of immunity
Function of the immune system
The immune system is a complex system of cells and responses that
recognises something as foreign and acts to remove it. For example microorganisms, foreign tissue, body cells that have become defective, eg cancer
In conclusion
The human body is a fascinating, intricate organism consisting of multiple
systems working together to keep the body in balance (homeostasis).
The purpose of this reading is to provide a brief overview of the human
body – how it is structured (anatomy) and it functions (physiology). The aim
is to set the scene for the changes associated with ageing and the common
conditions associated with ageing – this will be covered in Reading 2: Apply
basic knowledge of factors that support healthy functioning of the body.
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