The heart

Veins = TOVVARDS the heart

LOW pressure

Wall structure = THIN muscle + ELASTIC

THIN wall

WIDE lumen

VALVES

DE - OXYGENATED - except pulmonary = oxygenated

Artery = AWAY

HIGH pressure

Wall structure = ELASTIC and MUSCLE FIBRES

THICKEST wall

NARROW lumen

NO valves

 OXYGENATED blood – except Pulmonary artery =      deoxygenated

Capillaries = From ARTERIES - VIENS

LOW pressure

Wall structure = 1 layer of cell

very NARROW lumen

NO valves

Begins OXYGENATED ends DE-OXYGENATED.

Valves = Stop backflow of blood

Coronary arteries = supply heart w/ blood

Blood to heart tissue intrupted = heart attack