Science: Circulatory system - ch.3.3 Flashcards
4 functions of the circulatory system
- Carries nutrients and oxygen to cells
- Transports waste products to where they can be disposed of
- Distributes heat around the body
- Delivers hormones around the body
3 types of blood vessels
Arteries, veins and capillaries
Arteries
Carry blood away from the heart, to the rest of the body
Walls of arteries
They are thick due to the amount of pressure
Capillaries
- The walls are only one cell thick
- This allows materials to be exchanged between blood and body cells
- The finest of blood cells
What happens in the capillaries?
The materials needed by the cell exit and the waste enters the capillary
Veins + walls
- Carry blood back to the heart
- Lower pressure means they do not need thick muscular walls
In veins, how is blood pushed back to the heart?
by the contractions of the muscles next to them
What is the function of vein valves?
Valves ensure that blood cannot flow in the opposite direction by opening and closing
When do vein valves open?
when the blood is flowing toward the heart
When do vein valves close?
when the blood flows away
Heart + blood flow in heart
- Blood enters the atrium and exits the ventricle
- Pumps blood
Cardiac Muscle
Muscle in heart which does not tire.
Septum
Thick wall dividing the heart into two halves.
What is the function of the right heart pump?
Collects deoxygenated blood from the body and pumps it to the lungs
