Circulatory System 2

Question 1

Arteries

Answer 1

Carries blood away from the heart

Receive blood at high pressures (need to be elastic)

muscle/elastic tissues

The wall of the arteries are thick

Structure and function of arteries
Arteries are large and carry blood at a very high pressure.
Artery walls have a thick middle layer, containing both muscle and elastic tissue.
The muscle tissue provides strength, and allows the arteries to direct blood flow.
The elastic tissue allows the arteries to stretch and recoil.
Compared to their walls, arteries have a relatively narrow lumen, which keeps the blood pressure high.

Question 2

Capillaries

Answer 2

Exchange nutrients and oxygen with the tissues

-Lower blood pressure
-Lumen is tiny
-Really small
-Exchange substances with cells
-Single cell thick+permeable
(Take away C02)

Structure and function of capillaries
Capillaries are the smallest of the three blood vessels.
The role of capillaries is to exchange nutrients and waste products with the tissues.
Capillary walls are permeable, meaning substances are able to move through them.
Their walls are also only one cell thick which means a short distance for diffusion.
Capillaries carry blood at a low pressure and have a lower rate of flow than arteries.

Question 3

Veins

Answer 3

Transport blood back to the heart
-Smaller layer of elastic fibres+smooth muscles
-Biggest lumens
-They have valves to prevent backflow

Structure and function of veins

The role of veins is to carry blood from the body (or lungs) back to the heart.
Veins are a similar size to arteries, but they have relatively thin walls and a relatively small lumen
This is because they carry blood at a much lower pressure.
Veins also contain valves to prevent the blood from flowing backwards.