1.2.2 structure and functions of arteries, veins and capillaries

Arteries:

function:

• Carries blood away from the heart to the body.

Structure:

• Relatively small lumen to withstand high pressure

• Endothelium so it can fold and unfold

• Smooth muscle to relax and constrict the lumen

• Fibrous Collagen

• For strength

• Elastic fibers

• So it can stretch and recoil

Veins

Function: Helps blood return to the heart

Structure: Lumen is large and floppy to allow easy flow of blood.

The rest is the same as above.

Function: Exchange of gases

Structure:

One thin layer of endothelium only to allow rapid gas exchanges.