designed to open and close so that blood can flow in one direction

valve located between the left ventricle and ascending aorta

protective, fibrous membrane that surrounds the heart

The lower chambers of the heart

a dividing wall in the heart made of thick muscle that separates the right from the left side of the heart

valves that separate the atria from ventricles

blood vessels decrease in diameter

valve located between the right atrium and right ventricle, prevents backflow of blood into the right atrium

valve that separates the left atrium from the left ventricle, preventing backflow of blood into the left atrium

blood vessels increase in size

a blood vessel traveling AWAY from the heart

The thickest later of muscle tissue in the heart wall

Thin and fragile blood vessel, smallest in the body

blood vessel that carries blood BACK to the heart

vein that drains deoxygenated blood from upper body into the right atrium

smallest arteries

vein that drains deoxygenated blood from the body below the heart into the right atrium

arteries that wrap around the heart muscle and supply oxygenated blood to the atria and ventricles