animal tissue consisting predominantly of contractile cells

the hollow muscular organ located behind the sternum and between the lungs; its rhythmic contractions move the blood through the body

a specialized bit of heart tissue that controls the heartbeat

any of several muscles associated with the atrioventricular valves

a bundle of modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract

a node of specialized heart muscle located in the septal wall of the right atrium; receives impulses from the sinoatrial node and transmits them to atrioventricular bundle

the middle muscular layer of the heart wall

the hollow muscular organ located behind the sternum and between the lungs; its rhythmic contractions move the blood through the body