circulation

Functions of blood vessels

• carry blood

• exchange nutrients, waste, gases

• transport substances

• regulate blood pressure

• direct blood flow to tissues

Tunica intima

• innermost, simple squamous

• middle, smooth muscle with elastic & collagen

• outermost, connective tissue

Tunica media

• innermost, simple squamous

• middle, smooth muscle with elastic & collagen

• outermost, connective tissue

Tunica adventitia

• innermost, simple squamous

• middle, smooth muscle with elastic & collagen

• outermost, connective tissue

Arteries

• blood away from heart, thick (lots of elastic)

• exchange occurs between blood & tissue fluid

• blood toward heart, thick (less elastic)

Capillaries

• blood away from heart, thick (lots of elastic)

• exchange occurs between blood & tissue fluid

• blood toward heart, thick (less elastic)

Veins

• blood away from heart, thick (lots of elastic)

• exchange occurs between blood & tissue fluid

• blood toward heart, thick (less elastic)

Elastic arteries

• largest diameter, thickest walls (aorta & pulmonary trunk)

• medium to small, thick, smooth muscle cells & control blood flow to body regions

• small arteries

Muscular arteries

• largest diameter, thickest walls (aorta & pulmonary trunk)

• medium to small, thick, smooth muscle cells & control blood flow to body regions

• small arteries

Arterioles

• largest diameter, thickest walls (aorta & pulmonary trunk)

• medium to small, thick, smooth muscle cells & control blood flow to body regions

• small arteries