1. Cardiovascular System

2. Fitness for activities
Circulation
The muscles need to receive nutrients and oxygen. This is one of the three functions of the circulatory system.
What is the circulatory system?
Essentially it is a pumped system. Fluid is pumped around the body.
The fluid:
Transports nutrients and oxygen
Regulates your body temperature
Provides protection against disease

3. Fitness for activities
Circulation
Transports nutrients and oxygen
Lungs
Heart
Body
Oxygenated blood
Deoxygenated blood
Oxygenated blood circulates from the lungs to the rest of the body and back to the heart. It also carries glucose, other nutrients, water and waste all around the body.

4. Fitness for activities
Circulation
Regulates your body temperature
Lungs
Heart
Body
Oxygenated blood
Deoxygenated blood
As the blood gets close to the surface of your body, it loses heat quickly.
This is why your skin goes red when you exercise. Blood comes closer to the surface and loses heat, cooling you down.

5. Fitness for activities
Circulation
Provides protection from disease
Lungs
Heart
Body
Oxygenated blood
Deoxygenated blood
Antibodies, which fight infection, are transported around the body by the blood.
When exposed to the air, blood clots, sealing wounds from infection and beginning the process of repair.

6. Fitness for activities
Circulation
The key element of the circulatory system is the heart which is responsible for pumping the blood all around your body.
Right lung
Left lung

7. Fitness for activities
Circulation
The key element of the circulatory system is the heart which is responsible for pumping the blood all around your body.
Right lung
Left lung
Heart

8. Fitness for activities
Circulation
The key element of the circulatory system is the heart which is responsible for pumping the blood all around your body.
Aorta – carries oxygenated blood from the heart to the body
Right lung
Left lung

9. Fitness for activities
Circulation
The key element of the circulatory system is the heart which is responsible for pumping the blood all around your body.
Pulmonary arteries – carry used blood to the lungs to be reoxygenated
Right lung
Left lung

10. Fitness for activities
Circulation
The key element of the circulatory system is the heart which is responsible for pumping the blood all around your body.
Pulmonary veins – carry oxygenated blood from the lungs to the heart
Right lung
Left lung

11. Fitness for activities
Circulation
The key element of the circulatory system is the heart which is responsible for pumping the blood all around your body.
Superior vena cava – carries used blood to the heart from the upper body
Right lung
Left lung

12. Fitness for activities
Circulation
The key element of the circulatory system is the heart which is responsible for pumping the blood all around your body.
Inferior vena cava – carries used blood to the heart from the lower body
Right lung
Left lung

13. Fitness for activities
Circulation
Deoxygenated blood (blue in the diagram) returns from the body via veins and is pumped to the lungs.
The blood is then reoxygenated (red in the diagram) in the lungs and returned to the heart before it is pumped around the body again.
When the oxygen content has been reduced by the muscles, the cycle begins again.

14. Fitness for activities
Circulation
You can clearly see that each time blood is cycled around the body, it passes through the heart twice.
There are effectively two circuits for the blood to pass through.

15. Fitness for activities
Circulation
Lungs
Heart
Body
Oxygenated blood
Deoxygenated blood
We saw this earlier with a simplified diagram of the two circuits.
We can now look at this in a little more detail:

16. Fitness for activities
Circulation
Lungs
Here we see the functions of the four chambers of the heart.
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
Note that we are looking at the heart from the front so the left and right seem transposed.
Body

17. Fitness for activities
Circulation
Lungs
The right side of the heart pumps the deoxygenated blood from the body into the lungs.
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
In the lungs, the blood is reoxygenated.
Body

18. Fitness for activities
Circulation
Lungs
The left side of the heart pumps the oxygenated blood from the lungs into the body.
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
In the body, the muscles remove some of the oxygen as they “burn” energy.
Body

19. Fitness for activities
Circulation
Lungs
The pulmonary circuit is responsible for getting oxygen back into the blood.
Pulmonary circuit
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
It does this by pumping the blood from the heart, to the lungs and back into the heart again.
Body

20. Fitness for activities
Circulation
Lungs
The systemic circuit is responsible for getting oxygenated blood to where it is needed.
Right Atrium
Left Atrium
Right Ventricle
Left Ventricle
It does this by pumping the blood from the heart, to the body and back into the heart again.
Systemic circuit
Body
Remember that arteries carry blood out of the heart and veins carry blood into the heart.