November 2011
7 posts
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.