Transcript GCSE Physical Education

GCSE Physical Education
The Cardiovascular system
By the end of this topic you should
be able to:
 Describe
the Cardiovascular system
 Explain the immediate effects of
exercise, and the long term benefits of
regular exercise, on the cardiovascular
system.
 Explain how rest, diet, and drugs
affect the cardiovascular system.
Cardio-Vascular Fitness

‘The ability to exercise the entire body for long
periods of time.’

Cardiac
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
Vascular

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Of the heart
Of or containing vessels for conveying blood.
CV fitness has some benefit to all sports performers,
indeed to everyone, as it concerns the fitness of the
most important muscle in the body – the heart!
The Circulatory System

The Circulatory system consists of the:
 Heart
 Blood vessels
 Veins/arteries/capillaries etc…
 Blood
 Red/White blood cells, platelets, plasma.
 Pulmonary & Systemic circuits
Functions of the Circulatory System

Transport

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Control body temperature

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Oxygen and nutrients to parts of the body and remove toxic
products, such as Carbon dioxide from the body – the body
relies on these to keep alive. The balance of the nutrients also
keeps the body functioning properly.
The body is affected by changes of temperature, so keeping it
in an acceptable range keeps the body functioning properly.
Protection

Antibodies in the blood fight disease and platelets help to clot
the blood at the source of a cut and prevent germs entering
the body.
The Heart

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The Heart is a muscular pump
It is divided into two halves by a central
partition called the septum.
Each half is then divided by valves into an
atrium and a ventricle.
The right side of the heart deals with
deoxygenated blood; and the left deals with
oxygenated blood.
The Heart
The Heart

The Atria & Ventricles
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The atria are the top two chambers, and the
ventricles the bottom two.
The Septum
The Septum is the strong muscle that divides the
heart into two halves, preventing the deoxygenated
blood from mixing with the oxygenated blood.
 It is also the powerful muscle that contracts and
pumps the blood.

The Heart
The Double Circulatory System

The human body requires a double body
circulatory system, so that it can reoxygenate the blood at the same time as
circulating oxygenated blood around the
body.
Pulmonary Circuit
 Carries blood from the heart to the lungs and
back again.
 Systemic Circuit
 Carries blood from the heart to the rest of the
body and back again.

The Cardiac Cycle

Diastole
The atria passively fill with blood
 RA from the superior & inferior vena cava
 LA from the pulmonary veins
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Atrial systole
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The atria contract forcing blood into the ventricles
Ventricular systole
The ventricles contract forcing blood from the heart
 RV into the pulmonary artery
 LV into the aorta

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What are the immediate effects of exercise
on the heart?

The heart beats faster and
stronger to supply more oxygen
to the muscles.

This is caused by adrenaline, a
hormone released during
exercise.

Body temperature- muscles generate heat
which causes the body temperature to rise.

Sweat- To cool down the body produces
sweat.
ENERGY is needed to make the sweat
evaporate and this causes the
temperature to fall.

Lactic acid- when your muscles demand more
oxygen than can be supplied lactic acid builds up
causing muscle fatigue.
=
Blood Pressure

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Blood pressure is the force exerted by blood
on the walls of the arteries.
It increases during
exercise because more
blood is pumped around
the body, increasing
pressure on the blood
vessels.
A blood pressure meter
is used to measure
systolic & diastolic
pressure.
Blood pressure

Systolic BP

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The maximum pressure in the
arteries when the heart
contracts & pushes blood
through the aorta.
Diastolic BP
The pressure of the blood
during the relaxation phase of
the cardiac cycle.
 It depends mainly on the
elasticity of the arteries &
quality of the vessels.

How can I reduce the risk of high
blood pressure?
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Check your weight
Limit your alcohol consumption
Don’t smoke! Smoking damages the heart and
blood vessels & raises blood pressure.
Reduce salt intake
Avoid stressful situations that may cause anxiety
or worry.
Regular exercise
Heart rate (HR)
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Heart Rate
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The number of times the heart beats per
minute (bpm)
Can vary considerably from person to
person,
Average resting HR = 72 bpm

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Elite athlete e.g Lance Armstrong, Steve
Redgrave, Paula Radcliffe can have significantly
lower resting HR’s.
Max Heart Rate

220 - age
Stroke Volume (SV)
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The volume of blood ejected from the heart in
one heart beat.
At rest:
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approx 80ml
During exercise:
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up to 130ml
Cardiac Output (Q)

The amount of blood ejected from the heart in
one minute
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Cardiac Output = Heart Rate x Stroke Volume
Q
HR SV
Immediate effects of Exercise on the
Heart
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Muscles need oxygen to work.
During exercise the demand
for Oxygen is increased.
Therefore; the cardiac output
needs to be increased.
This is achieved by an
increase in Heart Rate and
Strove Volume.
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With increasing fitness the following occur:
 The heart pumps more blood every beat.
After
Before
Beats per minute
160
140
100
Recovery rate
= 5 mins
60
0
Beats per minute
Time (mins)
160
140
Recovery rate
= 2 mins
100
60
0
Time (mins)
Long term effects of exercise

Endurance training, commonly known as
aerobic/cardiovascular training, helps strengthen
the heart.
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With training the general size of the heart gets
bigger, the walls become thicker and stronger.
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20 mins + @ 60-80% of max HR
Myocardial hypertrophy.
Therefore:
The SV increases
 Resting HR decreases (bradycardia)
 Can work for longer at higher intensities.
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The effect of lifestyle on the
CV system
You will need to be able to explain:
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The need for rest & recovery time
The impact of diet on the CV system, in
particular how it can effect blood pressure and
cholesterol
The effects of recreational drugs
Rest
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Rest is essential for recovery and adaptation.
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Allows the heart to grow in size and thickness
 Myocardial hypertrophy
Increases the number of capillaries
 Capillarisation
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High cholesterol

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Cholesterol is a fatty substance
carried in the blood by lipoproteins.
Lipoproteins come in 2 forms:
 High Density (HDL)
 Low Density (LDL)
HDL contains more protein than fat & is referred to
‘good cholesterol’ because it carries cholesterol away
from the arteries to the liver which removes it.
LDL consists of mainly fat. It is the major cause of
cholesterol in the blood, & it can lead to a build up of
plaque which can restrict blood flow in the arteries.
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Blockages result in an increase in blood pressure
Diet
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Foods rich in HDL include:
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Fruit, vegetables, whole
grains & legumes (peas &
beans)
High cholesterol can be
caused by a diet high in
LDL’s, such as saturated
fat.
Socially Acceptable/ Recreational drugs
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Substances used on a
regular basis by many
people.
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Caffeine, nicotine, ethanol
(alcohol)
Smoking
Nicotine is not a banned drug.

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Increases risk of CHD by
damaging the heart and the
Oxygen carrying capability
of blood. It also damages
blood vessels and raises your
blood pressure.
Lowers HDL levels &
increases the tendency for
blood to clot
Alcohol
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Alcohol in moderation is thought to increase HDL &
so in the long term can help to lower blood pressure.
However, too much alcohol and binge drinking can
have serious adverse affects.
Sedentary lifestyle

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Inactivity means that the CV system does not
receive the benefits of exercise.
Also is a major contributory factor to the rise in
obesity.
Stress

Negative stress
build up over time
and can affect the
CV system by
leading to an
increase in blood
pressure & elevated
heart rate.