Blood Vessels

Blood vessels include:

• Arteries
• Arterioles
• Veins
• Capilleries

Artery structure and function

Arteries are made up of four layer. (starting from the inside)

• A lining layer of endothelium which creats a space in the middle called a lumen.
• An elastic layer
• A muscle layer
• Tough outer layer.

The muscle layer is very thick, this is to keep the blood at a high pressure and to prevent the wall from tering and blood getting out.

The elactic layer is also larger than normal. This is beacsue when the heart systoles the elastic layer strentches to accomidate the pressure change. When the heart disystoles the elastic layer recoils thus returning to a constant pressure.

There are no valves as the blood pressure is enough to maintain a flow of blood to the body with out any help. (also it goes with gravity)

Atrerioles structure and function

Aterioels are the passage that high pressure blood is transfered to the lower pressure of…