blood vessels and vascular shunt

What do artery’s do and their features

• they carry blood away from the heart at high pressure

• They have thick walls

• Elastic tissue (both of these needed to keep blood fastly flowing in 1 direction)

• Narrow lumen to maintain preasure

Whats an arterioles function and its features

• they are small branch arteries that control blood flow into capillary beds

• They vaso constrict and dilate - prioritise blood flow for example a vascular shunt

• They have a thick muscular layer

Whats a vascular shunt

• the redistribution of blood

What happens to the muscles and organs during exercise and rest

• The muscles during exercise vaso dilate

• The muscles during rest vaso constrict

• The organs during exercise vaso constrict

• The organs during rest vaso dilate

What are capillaries function and features

• they are the site of gas exchange and waste removal

• They are 1 cell thick - short diffusion distance

• Narrow lumen - slow blood down - diffusion

• Large surface area - increases gas exchange efficiency

What are pre capillary sphincters

• they are rings of smooth muscle at the entrance of capillaries

• They control blood into the capillaries

• When open the more blood enters capillary bed

• When closed the blood bypasses capillary bed via shunt vessel

What are venuels and their features

• they collect blood from capillaries and return to veins

• They have thin walls and low pressure

Function and features of veins

• they return blood to the heart at low pressure

• They have large lumen to reduce resistance for easy blood flow

• They have thin walls because of the low pressure so little muscle/elastic tissue is needed

• They have valves to prevent back flow - essential in legs