| A | B |
|---|
| mediastinum | space between the lungs in which the heart is located |
| pericardium | loose-fitting sac which encloses the heart |
| endocardium | thin membrane that lines the inner surface of the heart |
| foramen ovale | hole between the atria through which blood passes in the fetal heart |
| tricuspid valve | valve between the right atrium and right ventricle |
| mitral valve | valve between the left atrium and left ventricle |
| pulmonary semilunar valve | valve which prevents blood from the pulmonary artery from reentering the right ventricle |
| aortic semilunar valve | prevents blood from reentering the left ventricle as it enters the aorta |
| coronary arteries | supplies the heart itself with blood |
| sinoatrial node | pacemaker-embedded in the wall of the right atrium, initiates each heart beat, and thus sets the pace for the heart |
| 70-72 | number of times the average heart beats per minute |
| Purkinje network | nerve conducting system within the walls of the ventricles |
| right atrium | chamber which receives blood from all parts of the body |
| right ventricle | chamber which pumps blood the the lungs |
| left atrium | chamber which receives blood from the lungs |
| left ventricle | chamber which pumps blood out of the heart to all parts of the body |
| aorta | the largest artery in the body |
| superior and inferior vena cava | the largest veins in the body |
| arteries | carry blood away from the heart |
| veins | carry blood toward the heart |
| diastole | period of the filling of the atria |
| systole | period of active contraction |
| vagus nerve | when stimulated, releases acetylcholine, which inhibits the action of the heart by slowing the pacemaker |
| accelerator nerves | release norepinephrine, which increases the heart rate and strength of ventricular contraction |
| Bainbridge reflex | burst of speed by the heart due to increased pressure in the venae cavae and the right atriuim |
| electrocardiograph | instrument which measures and records the electric current in the heart |
| stethoscope | instrument that a physician uses to listen to the beat of the heart |
| infarction | a lack of blood supply destroys tissues of the heart |
| tachycardia | rapid heart beat |
