Blood Circulation
The effects of exercise     Heart disease


Blood Circulation
simplified diagram

Red = blood rich in oxygen
Blue = blood low in oxygen

Diagram showing blood circulation in the human body

Click here for a more detailed view of the heart
(You probabably wont need to remember the names for an exam. Check with your  teacher!)

Put oxygen into the blood and remove carbon dioxide

The heart is a pump. In fact it is TWO pumps.
The left side if the heart pumps blood around the body to supply cells with oxygen.
The right side pumps blood to the lungs where the blood picks up oxygen.

The heart contains valves to control the direction of blood flow.

Arteries   Blood vessels that carries blood away from the heart

Veins       Carry blood back towards the heart.

Capillaries   Tiny blood vessels that carry blood to the individual cells. Capillaries join the arteries to the veins.



  • i) Transports oxygen to the cells (carried out by the red blood cells)
  • ii) Transports waste away from the cells.
  • iii)Helps protect the body from infection  (carried out by the white blood cells)
  • iv) Helps keep us at 37º C

What is in blood

  • Red blood cells:   The red cells carry oxygen.
  • White blood cells  The white cells f ight disease
  • Platelets: The platelets help the blood clot
  • Blood plasma: the liquid part of the blood.
    Blood plasma is a pale yellow liquid and contains dissoved food

Red blood cells staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762.

Red blood cells

Heart disease
Heart disease can be caused by too much fat which clogs the arteries reducing the flow of blood to the heart. Exercise helps reduce the risk by speeding the flow up blood up which helps clear the arteries.

How to help reduce the risk of heart disease:

Take regular exercise

Eat a balanced diet that is low in fatty foods Don’t smoke (smoking can damage the arteries) Avoid too much alcohol

The effects of exercise on the body

When we take some form of exercise, e.g. running 400m, we need more oxygen because our muscles are working harder.This makes several things happen:

  • Our heart pumps faster to move the blood quicker We breath faster to get more oxygen.
  • We sweat to cool us down.


The Pulse
The pulse rate is the speed our heart pumps at and is measured in ‘beats per minute’

You can measure your pulse rate by pressing your fingers against your wrist or the side of the neck. You can feel the surge of blood every time your heart beats.You can use a stopwatch to time one minute and count the number of times your heart beats during that time.It is quite usual to count for just 15 seconds and then multiply the result by four to give you the final pulse rate.

Investigating the effect of exercise on pulse rate
In this experment we first measured our pulse while resting before the experiment One of the boys then ran up and down the stairs for five minutes. We took his pulse again as soon as the exercise was over and then again every five minutes.The results are recorded below


Heart Rate in beats per minute (b.p.m)
While resting  80
Immediately after 5 minutes exercise  190
5 minutes after the exercise  130
10 minutes after the exercise  100
15 minutes after the exercise  81

The pulse was either taken at the wrist  (where an artery is near the surface of the body) or the side of the neck just beside the windpipe.
Conclusion Our results showed us that the heart rate increased rapidly after exercise and then gradually dropped back to normal. The time taken  for the pulse to drop back to normal is called the recovery periodand is sometimes used as a measure of fitness (the quicker the recovery period, the fitter you are)