Semilunar Valves

-When ventricles contract their pressure is lower than that of the major arteries

-^Semilunar valves are shut

-When the pressure rises above that of the arteries they open

-When the heart starts to relax the pressure drops quickly and they’re shut again

Atrioventricular Valve

-Remain open while atria contract

-When pressure in ventricles rises above that of atria the blood tries to move back up

-This fills valve pockets and valves snap shut

Systole

-Heart muscle contracts

-Blood is pumped from chambers into arteries

Diastole

-Blood pressure at it’s lowest

-Ventricles are relaxed

-Heart fills with blood

Atrioventricular Node

Receives wave and sends it down the purkyne tissue in the septum.

Sinal Artial Node

Initiates a wave of excitation, approx 55-80 times a minute.