Summary Blood vessels and tissue fluid

BLOOD VESSELS

ARTERIES:
● Carry the blood away from the heart
● high blood pressure
● thick walls
● Smaller lumen than veins
● lots of elastic tissue to smooth the flow of the blood
● lots of smooth muscle
● lined with smooth endothelium to reduce friction

ARTERIOLES
● Branch off of arteries
● thinner walls
● less muscular walls
● feed the blood to the capillaries

CAPILLARIES
● Smallest blood vessel
● site of metabolic exchange
● walls are only one cell thick for fast exchange
● leaky walls (holes/ pores in the walls)

VENULES
● Larger than capillaries
● smaller than arteries and veins

VEINS
● Carry the blood into the heart
● large lumen
● thin walled as the blood pressure is low
● little elastic tissue
● contain valves to prevent backflow of the blood