Transcript The Circulatory System. - PhysicalEducationatMSC

The Circulatory
System.
The Circulatory System
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The circulatory system is made of:
The Heart
Arteries and Arterioles
Veins and Venules
Capillaries
Blood
Functions
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Circulate blood to all parts
of the body
Transport water, oxygen and
nutrients to cells
Remove wastes, including
carbon dioxide, from cells
Maintain body temperature
The Heart
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Composed of four chambers
Two Atria (upper chambers) & two Ventricles
(lower chambers).
The Atria receive blood from the body, the
ventricles pump blood back out into the body.
The Heart
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The Septum divides the
heart into two pumps.
The left pump is the left
atrium and left ventricle –
full of oxygen rich blood
from the lungs which gets
pumped around the body.
The Heart
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The right pump is the
right atrium and right
ventricle – full of deoxygenated blood from
the body, gets sent to
lungs to get rid of
carbon dioxide and pick
up oxygen.
Anatomy of the Heart
Heart Function
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The blood from the left pump (oxygen rich)
does not mix with that of the right pump
(oxygen poor), the septum of the heart keeps
them separate.
For blood to make a complete circuit around the
body it passes through the heart two times.
Features of the heart
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Located slightly left of the sternum
The adult heart is about the size of a large fist
At rest, the average heart-rate is 72 beats per minute
Maximum Heart-rate = 220 – age
At rest the heart pumps 5 litres of blood per minute
During maximum work it can pump over 30 litres per
minute.
The Circulatory
System
PART B
Blood Vessels
Arteries – Arterioles –
Capillaries – Venules –
Veins.
Arteries
 The aorta is the largest
artery in the body. The
left ventricle pushes the
blood into the aorta and
onto the rest of the
body.
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Arteries
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The artery walls are
elastic so they are able to
expand with each
heartbeat to
accommodate blood.
When you take your
heart rate, you are feeling
the pressure of the
blood being pushed into
the arterial system.
Arteries
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Arteries further reduce in size to become
arterioles as the network of blood vessels work
their way into the depths of the body.
Bleeding from an artery can be recognised by
the blood spurting out with each heart beat and
by its bright red (oxygen rich) colour.
Arteries
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Coronary Artery – supplies the hearts chambers
with oxygen and nutrients.
Heart attacks are often caused by a blockage of
the coronary artery.
Smoking, drinking, eating fatty foods and lack
of exercise contribute to coronary artery
blockages.
Capillaries
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The exchange of
nutrients and waste
between the body and
blood cells occurs in the
capillaries.
Heat from cells is also
absorbed into blood
through the capillaries
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Exchange of materials is easy
as capillaries are only one cell
thick.
When you begin to exercise
capillaries dilate to allow
increased blood flow.
Other capillaries come into
use through the opening of
pre-capillary sphincters.
Capillaries
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A long term exercise program may increase the
number of capillaries supplying blood to
muscles, allowing an increased oxygen supply to
muscle and removal of wastes.
Veins
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Veins carry blood back to the heart.
Veins have no pulse, blood flow is steady and
constant.
The walls of veins are thin and not as elastic as
artery walls.
Veins.
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The return of blood to
the heart depends on
contraction of skeletal
muscle.
Veins are squeezed by
muscle as they contract.
One way valves working
against gravity and
prevent backflow of
blood to organs and
muscles.
Veins.
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Blood Pooling after exercise is a problem if
you don’t cool down.
During a warm down, the muscle pump system
continues to move the gradually diminishing
excess blood flow around the body until it has
reached a resting level.
Homework
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Complete “Circulatory System Homework Sheet
2”
The Circulatory
System
PART C
Blood
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Red Blood cells:
Make up 99% of all
blood cells
Carry oxygen to, and
carbon dioxide from, the
cells and muscles.
Have a life span of four
months
Blood
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White Blood Cells:
Exist in the body in a ratio
of 1:700 red blood cells.
Have a role in immune
function
Have a life span of a few
days.
Platelets:
Cause blood to clot when
blood vessels are damaged.
Path of Blood Around the Body
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Oxygenated blood travels from the lungs to the left
atria..
It goes down into the left ventricle which then squeezes
it out the Aorta into arteries and to the muscles,
organs, brain etc..
Oxygen,water and nutrients are dropped off, Carbon
dioxide and wastes are picked up at the capillaries….
Path of Blood Around the Body
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De – oxygenated blood travels back to the right atria
via the veins..
Deoxygenated blood moves from the atria into the
right ventricle..
Deoxygenated blood is pumped from the right ventricle
to the lungs, where it drops off carbon dioxide (plus
water plus heat) and picks up oxygen..
The cycle then continues..
In short…
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Oxygenated blood  lungs  left atria left
ventricle  arteries  arterioles  capillaries
(drop off O2, pick up CO2)…
Deoxygenated blood capillaries venules
 veins  right atria  right ventricle 
lungs(drop off CO2, pick up O2)..
Blood pressure
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Blood pressure is caused by the
ventricles contracting.
In arteries it fluctuates with each
heart beat.
The higher pressure (systolic)
occurs when the ventricles
contract.
The lower pressure (diastolic)
occurs when the ventricles relax.
Blood pressure is usually described
by these two limits
Average blood pressure is
120/80mmHg
Blood pressure
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In mammals, the chambers of the heart contract
rhythmically and spontaneously under the
control of certain group of heart muscle cells
called nodes.
Sinoatrial and Atrioventricular.
Exercise & the
Circulatory System
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The benefits of a long term exercise program on the
circulatory system are:
Greater efficiency of the heart
Lower resting heart rate
Increase in left ventricle size
Lower blood pressure
Greater blood volume
Increase in haemoglobin count.
Important Terms
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Stroke Volume – the amount of blood pumped
into the systemic circuit with one heart beat.
Avg. Adult female = 60ml
Avg. Adult Male = 80ml
In an endurance trained male under maximal
conditions it could reach 160ml!
Important Terms
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Cardiac Output – the amount of blood the
body pumps in one minute. Around 5 litres at
rest, up to 30 litres under maximum effort.
Cardiac output = Q
Stroke Volume = SV
Heart Rate = HR
Q= SV x HR
Homework
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Complete Circulatory System Homework Sheet
3