GCSE PE

1
GCSE PE
The Circulatory System
2
The Circulatory System
The circulatory system is also known as the
cardiovascular system.It consists of
3. The Heart
1. Blood
2. Blood Vessels
The three main types of blood vessels are
arteries, veins and capillaries.
3
Functions of the Circulatory system

• Transport oxygen and nutrients to parts of the
  body and remove waste or toxic products from the
  body
• Control of body temperature
• Protection against disease

4
Circulatory System Functions - Transport
All the cells of the body require energy in order
to work properly, e.g. muscle cells would not be
able to contract without a supply of oxygen and
fuel.
The circulatory system is therefore the bodys
transport system.It carries

• Blood from the heart to all the cells of the
  body, providing them with fuel and oxygen.

• Waste products away from all the cells of the
  body, including carbon dioxide and urea.

It is a delivery service
and a waste disposal unit!
5
How Blood is Pumped around the Body
Lungs

• Blood flows around the body in a figure of
  eight circuit, passing through the heart twice
  on each circuit.

(A)
(A)

• Blood travels away from the heart through
  arteries (A).

(V)
(V)

• Blood returns to the heart through veins (V).

Heart
There are 2 separate loops to the circuit

• The top loop carries blood from the heart to
  the lungs and back.

Body

• The bottom loop carries blood from the heart to
  all over the body and back.

6
How the Heart Pumps Blood
The heart is divided into 2 parts. Each part is
a pump, so the heart is a double pump.
To the lungs
Tothe body
From the body
From the lungs
The right side pumps deoxygenated blood to the
lungs to pick up oxygen.
The left side pumps oxygenated blood to the rest
of the body for use.
7
The Cardiac Cycle - How the Heart Beats
Every time the heart beats it goes through a
3-part cycle

• Stage 1
• The top chambers (atria) relax and fill up with
  blood from the veins.

• Stage 2
• The atria contract and the blood is forced into
  the relaxing bottom chambers (ventricles).

• Stage 3
• The ventricles contract and the blood is forced
  out of the heart into the arteries.

8
Pulse Rates

• Pulse rates are caused by the action of theheart
  as it pumps blood around the body.

• Every time the heart beats (contracts) it can be
  felt as a pulse, due to the pumped blood making
  the artery walls expand andthen contract.

• It can be measured wherever an artery passes
  close to thesurface of the skin.

9
Pulse Rates
Temporal Pulse Found just over the temple on
either side of the forehead.
The four main pulse rate points of the body are
Carotid Pulse Found on either side of the neck to
the side of the windpipe.
Radial Pulse Found at the base of the thumb on
the inside of each wrist.
Femoral Pulse Found at the top of each leg in the
groin.
10

• Resting heart rates can vary between people, due
  to sex, age and health
• Average resting heart rates are between 60 and 80
  beats per minute
• Fit people will have a much lower heart rate
  (e.g. an endurance athlete may have a resting HR
  of 30 beats per minute)
• This is because their hearts are stronger and
  bigger and are able to pump more blood in fewer
  beats than an unfit people
• Their stroke volume is therefore greater
• Resting heart rates can be one way to show levels
  of fitness
• The speed at which heart rate returns to normal
  after exercise is called the recovery rate
• The quicker this returns to normal, the fitter a
  person is

11
Blood Pressure
Blood pressure is a measure of the outward force
exerted by the blood on the walls of the blood
vessels.
It varies throughout the body and at different
times in the cardiac cycle. Arteries have a
higher pressure than veins.
Blood pressure is
lower in veins which are further from the
beating heart and found after the capillary beds
(which reduce the blood pressure).
higher in the arteries which are relatively
close to the source of the pump (heart).
12
Measuring Blood Pressure
Blood pressure is measured using a
special machine called a Sphygmomanometer.
It is always taken in the upper arm.Two readings
are taken

• Systolic pressure this is the arterial pressure
  produced when the right ventricle contracts.

• Diastolic pressure this is the arterial
  pressure when the right ventricle relaxes.

The final reading is taken as a fraction, with
systolic at the top and diastolic at the bottom.
The average blood pressure for a 15 year old is
120/80.
13
Measuring Blood Pressure
There are several different types of
Sphygmomanometer available
It is important to look after your
cardio-vascular fitness, by having a balanced
diet and regular exercise, for all of your life.
14
What will affect blood pressure?

• Age (increases with age because our arteries are
  less elastic)
• Exercise
• Stress (causes hormones to be released which
  increases bp)
• Smoking (increases bp because nicotine reduces
  the efficiency of our capillaries)
• Diet (High fat /or salt diet increases bp
  because fatty deposits block and harden arteries)
• Weight (more weight increases strain on the
  circulatory system)

15

• During physical activity the heart beats faster
  and pumps out more blood
• Blood pressure rises
• Regular physical activity can lower your resting
  blood pressure

16
Definitions of Heart Function
There are three ways to measure heart performance
in sport and exercise

• Heart Rate
• Stroke Volume
• Cardiac Output

Heart Rate
Stroke Volume
The amount of blood pumped by the heart in one
beat
The number of times the heart beats per minute.
64 beats per minute is a typical result for a fit
person at rest.
17
Cardiac Output
Cardiac output is
the amount of blood pumped by the heart in one
minute.
It is calculated using the formula
Cardiac Output Stroke Volume x Heart Rate
18
Calculating Cardiac Output
For example
While exercising
At rest
Stroke Volume 75 ml Heart Rate 65
b.p.m. Cardiac Output 75 x 65
4875 ml
Stroke Volume 150 ml Heart Rate 200
b.p.m. Cardiac Output 150 x 200
30000 ml
19
During sport.

• We want to increase the amount of blood going to
  the working muscles (cardiac output)
• We can do this by either increasing
• Stroke volume
• Heart rate
• Both

20
How does the Circulatory System Contribute to
Performance in Sport?
The circulatory system is the bodys

• Delivery service for oxygen, glucose water.
• Waste disposal unit for carbon dioxide.
• Temperature control system together with the
  skin.

As a result, the circulatory system allows us to
effectively live, move and undertake everyday
tasks and perform in a wide variety of physical
activities.
21
Athletics The Marathon
A full marathon run is 26.2 miles. In order to
allow the body to complete such a demanding task
the circulatory system must

• Supply the working muscles, especially in the
  legs and arms, with greater supplies of both
  oxygen and glucose so they can continue to
  contract and create movement.

• Remove lactic acid and carbon dioxide from the
  body so the athlete can continue to run well and
  without pain.

• Reduce body temperature while running via the
  blood and sweating, so running speed can be
  maintained.

22
What happens to our circulatory system when we
exercise?

• The hormone adrenalin is released
• Causes our heart rate to increase
• Heart contracts more powerfully therefore stroke
  volume increases
• Increased cardiac output
• Increased supply of oxygen and fuel to working
  muscles
• The oxygen going to the muscles can be up to 3x
  the resting amount
• Blood flow can be increased up to 30x
• Therefore, working muscles can receive up to 90x
  the amount of oxygen they receive at rest