coronary circulation and muscle cardiac cells

aorta gives rise to

right and left coronary artery

what does the left coronary artery branch into and what does it supply

branches into anterior interventricular artery and circumflex artery; supplies anterior and left regions of heart

what does right coronary artery branch into and what does it supply

branches into posterior interventricular artery and marginal artery; supplies post and right regions of heart

why is the left ventricle larger thicker and more powerful

it must pump blood to the body

low O2 blood returns to the heart via 

coronary sinus that receives blood from great and middle cardiac vein 

when do AV valves open and close

open to allow blood to flow from atria to ventricles, close when ventricles to prevent blood backflow

what contract with ventricles, pulling AV valves close so no prolapse and backflow happens

papillary muscles

walls of atria are lined with 

pectinate muscles 

when do semilunar valves open and close

open when ventricles contract and close when ventricles relax

what is the fibrous skeleton made of, attach to, and provide

bands of ct around hearts valves, attach vales and cardiac muscle cells to heart, and provides electrical insulation b/w atrial and ventricular cells

what are two cardiac muscle cell types 

conducting system cells (generate action potential) and contractile muscles (contract to pump blood of heart, 99% of cardiac muscle cells)