| P Wave | Represents atrial function, specifically depolarization or excitation of the atria |
| QRS Wave | Represents ventricular function, specifically the excitation of the ventricles |
| T Wave | Represents the relaxation phase from the contraction of the ventricles |
| Aorta | Largest artery in the body |
| Aortic Valve | Valve between the left ventricle and aorta |
| Apex | Pointed end of the heart |
| Artery | A large vessel that carries blood away from the heart |
| Atrioventricular Bundle | Specialized muscle fibers in the interventricular septum that carry electrical impulses to the ventricles |
| Atrioventricular Node (AV Node) | Specialized tissue in the interatrial septum; carries impulses from the SA node to the walls of the ventricles |
| Atrioventricular Valves (AV Valves) | Valves between the atria and ventricles |
| Atrium | 2 upper heart chambers |
| Base | Cranial portion of the heart |
| Bicuspid Valve | Valve between the left atrium and left ventricle |
| Bifurcate | Splitting into 2 branches |
| Capillaries | Smallest blood vessel |
| Carbon Dioxide (CO2) | Gas released by tissue cells and transported to the heart and lungs for exhalation |
| Coronary Arteries | Supply blood and oxygen to the myocardium |
| Deoxygenated Blood | Oxygen-poor blood |
| Diastole | The relaxation phase of the heartbeat |
| Endocardium | Inner lining of the heart |
| Myocardium | Muscle layer of the heart |
| Oxygen (O2) | Gas that enters the blood through the lungs and travels to the heart to be pumped to the rest of the body |
| Oxygenated Blood | Oxygen-rich blood |
| Pericardium | Membrane surrounding the heart |
| Pulmonary Artery | Artery that carries deoxygenated blood from the heart to the lungs |
| Pulmonary Circulation | Flow of blood from the heart, to the lung, and back to the heart |
| Pulmonary Valve | Valve between the right ventricle and pulmonary artery |
| Pulmonary Veins | Veins that carry oxygenated blood from the lungs to the heart |
| Septum | Partition |
| Sinoatrial Node | Pacemaker of the heart |
| Sinus Rhythum | Normal heart rhythm |
| Systematic Circulation | Flow of blood from the body cells to the heart and back out to the body cells |
| Systole | Contraction phase of the heart |
| Valves | Structures in veins and in the heart that temporarily close an opening so that blood can flow in one direction |
| Vein | Thin-walled vessel that carries blood toward the heart |
| Vena Cavae | Largest vein in the body |
| Vantricles | 2 lower chambers of the heart |
| Aneurysm | Sac formed by weakening of a blood vessel. Can cause hemorrhage and stroke |
| Arrhythmia | Abnormal heart rhythm |
| Asystole | Without contraction; lack of heart activity |
| Atherosclerosis | Hardening of arteries due to plaque buildup |
| Auscultation | Listening with a stethoscope to sounds within the body |
| Cardiac Tamponade | Compression of the heart due to fluid or blood in the pericardial sac |
| Congenital Heart Disease (CHD) | Abnormalities of the heart at birth |
| Congestive Heart Failure (CHF) | Heart is unable to pump its required amount of blood |
| Capillary Refill Time (CRT) | The time it takes for the mucous membranes to return to a normal pink color after applying finger pressure |
| Defibrillation | Use of electrical shock to restore normal heart rhythm |
| Echocardiogram (ECHO) | High-frequency sound waves and echoes that produce an image of the heart |
| Embolism | Blockage of a vessel by a clot or foreign material |
| Embolus | A detached, moving clot |
| Fibrillation | Rapid, random, and irregular contractions of the heart |
| Flutter | Rapid but regular contractions of the atria and ventricles |
| Hypertension | Increased blood pressure |
| Hypotension | Decreased blood pressure |
| Hypoxia | Decreased oxygen to tissues |
| Infarction | Area of dead tissue |
| Ischemia | Lack of blood flow to tissues |
| Ligate | To tie off a vessel to prevent bleeding or to constrict tissue using ligature |
| Murmur | An extra heart sound |
| Occlusion | Blockage; obstruction or closure of body passage |
| Patent | Open; unobstructed |
| Patent Ductus Arteriosus (PDA) | Condition in which the small duct between the aorta and pulmonary artery, which normally closes after birth, remains open |
| Perfusion | Passage of fluid through the blood vessels of a specific organ; blood flow through the tissue |
| Pericardial Effusion | Escape of fluid into the pericardial sac leading to cardiac tamponade |
| Premature Ventricular Contraction (PVC, VPC) | Ventricles are triggered to contract by the Purkinje fibers rather than the SA node |
| Shock | Inadequate tissue perfusion |
| Sphygmomanometer | Instrument that measures arterial blood pressure |
| Stent | Small expander inserted into tubular structures such as vessels to provide support and prevent collapse |
| Stethescope | Instrument used to listen to sounds within the body |
| Thrill | Vibration felt on palpation of the chest |
| Thrombus | Stationary clot attached to the wall of a vessel |
| Ventricular Septal Defect (VSD) | Small hole(s) in the interventricular septum |
| Vasoconstriction | Narrowing of a vessel |
| Vasodilation | Expansion of a vessel |
| White Lead | Right front |
| Green Lead | Right rear |
| Black Lead | Left front |
| Red Lead | Left rear |
