Download the circulatory system

THE CIRCULATORY SYSTEM
The Circulatory System is the transport system of
the body.
The functions of the Circulatory system are:
 It transports oxygen, nutrients and
hormones to all parts of the body.
 It collects waste and carries it to the
excretory organs, e.g. kidneys
 It defends the body against infection

The Circulatory System is made up of blood, blood
vessels and the heart.
Blood
We need blood in our bodies to stay alive. Adults have
about 5 liters or 9 pints of blood circulating inside
their bodies, delivering oxygen and nutrients while
removing wastes such as carbon dioxide from cells.
FUNCTIONS OF BLOOD
Transportation
 Protection
 Temperature Regulation
 Maintaining body’s equilibrium
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THE BLOOD CONTAINS:
 Red
blood Cells/ Hemoglobin-Transports
oxygen and nutrients.
 White blood cells/ Leukocytes-These protect
against foreign bodies that enter our
bodies
 Plasma- A clear liquid, which makes up
about 55% of blood. The liquid plasma
carries the solid cells.
 Platelets- This helps the blood to clot.
Without blood platelets, one would bleed to
death.
BLOOD VESSELS
Blood flows inside blood vessels on its journey
to all parts of the body. Blood vessels in the
body include:
Arteries- carry blood away from the heart.
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Veins- carry blood back to the heart.
Capillaries- the smallest blood vessels. Red blood
cells inside the capillaries deliver oxygen and
nutrients to body tissues as they remove
carbon dioxide and other waste.
THE HEART
The heart is the pump which circulates the blood to
all parts of the body. The heart has four hollow
chambers:
The right atrium
 The right ventricle
 The left atrium
 The left ventricle.
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Blood flows into these before it is pumped to all
parts of the body.
THE HEART CONT’D
In the heart there are also four valves which
prevent the back flow of blood. Two are located
between the atria and ventricles which are the
tricuspid (right side) and bicuspid (left side)
valves. The others are found between the heart
and the arteries leaving the heart called the semi
lunar valves
The septum is a wall that runs down the middle of
the heart dividing it into two parts. The walls of
the heart is made up of cardiac muscle
Since the heart is divided down the middle each
part is a pump, so the heart is double pump for
double circulation.
The right side pumps blood to the lungs and then
returns it to the heart. This is known as pulmonary
circulation.
The left side pumps blood to the body and then it
returns it to the heart. This is called systemic
circulation
BLOOD CIRCULATION AROUND THE BODY
BLOOD CIRCULATION AROUND
THE BODY.
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Deoxygenated blood enters the right atrium through the
inferior and superior vena cava.
The blood is pumped to the right ventricle.
The right ventricle contracts and forces the blood
through the pulmonary artery to the lungs.
In the lungs, the blood becomes oxygenated and it flows
back to the heart through the pulmonary vein to the left
atrium.
The blood, rich in oxygen is pumped to the left ventricle.
The thick muscular wall of the left ventricle contracts
and pumps the blood through the aorta to all parts of
the body.
The blood eventually returns to the heart and the cycle
continues.
BLOOD CIRCULATION AROUND THE
BODY.
THE CARDIAC CYCLE
The average person’s heart beats about 72 times
per minute. Each heartbeat is a cardiac cycle
which had three main stages.
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ATRIAL SYSTOLE- the contraction of the atria
which pump blood in to the ventricles.
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VENTRICULAR SYSTOLE- the contraction of
ventricles which pump blood to all parts of the body.
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COMPLETE CARDIAC DIASTOLE- the relaxation
of the atria and ventricles allowing blood to enter the
heart
PULSE
Your heartbeat can be felt and counted via one’s
pulse in arteries just below the skin. The pulse is a
person’s heart rate which occurs when the left
ventricle contracts and forces blood into the aorta.
There are two places where a pulse is mainly
checked.
 The radial artery found on the inside of the wrist
 The carotid artery found in the neck
BLOOD PRESSURE
Blood pressure depends on how much blood flows
into a blood vessel and how easily it can flow out.
In terms of a person’s blood pressure we refer to it
as the measurement of blood pressure in the large
artery found above the elbow.
Blood pressure is measured in two ways
 Systolic Pressure - the measurement when the
left ventricle of the heart contracts
 Diastolic Pressure – the measurement when the
left ventricle of the heart is relaxed
BLOOD PRESSURE
Blood pressure is expressed as a fraction
systolic pressure
diastolic pressure
Average blood pressure is 120/80 measured in
millimetres of mercury
THE EFFECT OF THE CIRCULATORY
SYSTEM ON OTHER SYSTEMS.
The circulatory system is very important
for the functioning of all the other systems
of the body. All systems rely on it to
supply them with oxygen and nutrients
while removing waste such as carbon
dioxide. If the Circulatory System stops
functioning the other systems will also
stop functioning and this can lead to
death.
THE EFFECTS OF EXERCISE ON
THE CIRCULATORY SYSTEM.
Exercise can improve the Circulatory System
in the following ways:
 The heart pumps more blood per beat.(stroke
volume increases)
 The heart’s recovery rate becomes quicker.
 The resting heart rate becomes lower.
 The number of capillaries in the body
increases.
 Increase cardiac output. This means that the
heart beats faster
THE END