Understand how the structures of blood vessels (capillaries, arteries and veins) relate to their functions

Arteries, Veins and Capillaries

• Blood is transported through tissues via the blood vessels
• Blood is taken away from the heart via the arteries
• This reaches the tissues via the capillaries
• Blood is entered in to the heart via the veins
• Each blood vessel has a space called a lumen

Artery Structure

• It has collagen fibres which makes them strong and durable which also contain elastic fibres to allow them to stretch and recoil
• It has smooth muscle (tunica media) which allows them to constrict and dilate
• It can contract using its thick muscular layer.

Capillary Structure:

• It is a thin blood vessel as the endothelium is one cell thick
• Substances exchange easily
• It has a high resistance to blood flow as blood is slowed down.
• This gives time for efficient exchange of chemicals at tissues

Veins Structure:

• It has collagen fibres which makes them strong and durable which also contain elastic fibres to allow them to stretch and recoil
• It has smooth muscle (tunica media) which allows them to constrict and dilate
• It has semi-lunar valves which prevent the backflow of blood

The pressure in the arteries is the highest:

• The closest to the ventricles
• They contract forcefully themselves
• Capillaries are the highest pressure due to the…