ch 9.1 heart terms

semilunar valve that prevents backflow of blood from aorta to heart

rounded tip of heart, pointing left and downward

ear-shaped continuation of left and right upper part of atria

located in right atrium near lower portion of interatrial septum and composed of small mass of atypial cardiac muscle tissue

valves betwee atria and ventricles of heart (left valve is bicuspid or mitral valve and right valve is tricuspid in some species)

left or right upper chamber of heart

band of specialized cardiac muscle fibers that arise in atrioventricular node and branch down on both sides of interventricular septum, transmitting atrial contraction rhythm to ventricles

tendinous strings resembling cords that extend from cusps of atrioventricular valves to papillary muscles of heart

upper, anterior angle of right ventricle where pulmonary artery begins

heart

blood vessels of the heart

leafletlike segment of cardiac valve

relaxation stage of heart action

blood vessel present in fetal circulation that connects pulmonary artery to descending aorta

endothelial membrane lining chambers of heart

outermost serous layer covering heart

opening between atria in fetal heart, normally closed after birth

between ventricles

thick middle muscle layer of heart wall

sinoatrial node, which initiates heartbeat and regulates its rate

external layer of membrane covering heart

valve at base of pulmonary artery (semilunar valve)

specialized cardiac muscle fibers that are involved in impulse-conducting system of heart

the half-moon-shaped valves at base of pulmonary artery and aorta

initiates heartbeat and regulates its rate (pacemaker)

contraction stage of heart action

membranous structures in passages that close to prevent reflux of contents