CARDIOVASCULAR

ricle. 4. Apex: Pointed end of the heart, the location of the point of maximum impulse. 5. Atria: Upper chambers of the heart; receive blood. 6. Atrial diastole: Relaxation of atria. 7. Atrial systole: Contraction of atria. 8. Atrioventricular (AV) node: Group of pacemaker cells that relays impulses from the atria to the ventricles. 9. Atrioventricular Valves1. Afterload: Pressure against which ventricles must pump blood. 2. Aorta: Carries blood from left ventricle to body. 3. Aortic valve: Heart valve that prevents backflow from the aorta to the left vent: Valves between atria and ventricles (Tricuspid and Mitral). 10. Atrium: Upper chamber of the heart. 11. Automaticity: The unique ability of the cardiac muscle to contract without nervous stimulation. 12. Baroreceptor Reflex: Regulates heart rate and stroke volume in response to blood pressure changes. 13. Baroreceptors: Pressure sensors in the aorta and carotid arteries that detect changes in blood pressure. 14. Base: Broadest part of the heart where great vessels enter and leave. 15. Bicuspid Valve: AV valve between left atrium and ventricle. 16. Cardiac Cycle: Repetitive pumping action which includes contraction and relaxation. 17. Cardiac Muscle: Contains 1 centrally located nucleus, branching cells, rich in mitochondria, striated. 18. Cardiac Output: Volume of blood pumped by a ventricle in 1 min (CO = HR × SV). 19. Chambers and Blood Vessels: Includes left atrium, right atrium, left ventricle, right ventricle. 20. Chemoreceptor Reflex: Mechanism where chemicals affect heart rate and stroke volume. 21. Chemoreceptors: Sensors that detect levels of carbon dioxide, oxygen, and pH. 22. Chordae Tendineae: Fibers supporting AV valve flaps. 23. Coronary Arteries: Supply blood to the heart wall. 24. Coronary Sinus: Drains blood from heart muscle to the right atrium. 25. Depolarization Phase: Na+ and Ca2+ channels open. 26. Diastole: Period of cardiac muscle relaxation. 27. Electrocardiogram (ECG): Recording of electrical activity of the heart. 28. Endocardium: The endothelial membrane that lines the chambers of the heart. 29. Epicardium: The serous membrane on the surface of the myocardium. 30. Epinephrine: Hormone that can increase heart rate and stroke volume. 31. Factors Modifying Basic Heart Rate: Includes neural controls, hormones, and physical factors. 32. Heart Characteristics: Size of a fist, weighs less than 1 lb, located between lungs. 33. Heart Coverings: Pericardium: double-layered sac that protects the heart. 34. Heart Layers: Epicardium, myocardium, endocardium. 35. Heart Rate: Number of heart beats in 1 min, approximately 72 beats/min. 36. Heart Sounds: First sound is "lubb," second is "dupp." 37. Inferior Vena Cava: Drains blood from below the diaphragm. 38. Interatrial Septum: Wall separating right and left atria. 39. Interventricular Septum: Wall separating right and left ventricles. 40. Left Coronary Artery: Supplies blood to the anterior heart wall 41. Major Blood Vessels: Includes superior vena cava, renal arteries, and pulmonary veins. 42. Mediastinum: Space between the lungs. 43. Mitral Valve: Valve regulating blood flow between left atrium and ventricle. 44. Murmurs: Abnormal heart sounds due to faulty valves. 45. Myocardium: Middle layer of the heart wall, composed of cardiac muscle. 46. Nervous Regulation: Mechanism of the nervous system regulating heart function. 47. Pacemaker Potential: Membrane changes initiating cardiac action potentials. 48. Parasympathetic Nervous System: Slows heart rate primarily via the vagus nerve. 49. Pericardial Cavity: Space around the heart containing serous fluid. 50. Pericardium: Membranous sac enclosing the heart. 51. Physical Factors: Age, gender, exercise, and body temperature affecting heart rate. 52. Plateau Phase: Ca2+ channels remain open, prolonging action potential. 53. Preload: The amount of stretch in the ventricular muscle before contraction. 54. Pulmonary Circuit: Carries deoxygenated blood to lungs. 55. Pulmonary Trunk: Splits into right and left pulmonary arteries. 56. Pulmonary Valve: Prevents backflow from pulmonary artery to right ventricle. 57. Purkinje Fibers: Distribute the impulse throughout the ventricles for contraction. 58. P Wave: Represents atrial depolarization. 59. QRS Complex: Represents ventricular depolarization. 60. T Wave: Represents ventricular repolarization. 61. Stroke Volume: Volume of blood pumped per ventricle per contraction (~70 ml). 62. Ventricles: The two lower chambers of the heart. 63. Ventricular Diastole: Relaxation of ventricles. 64. Ventricular Systole: Contraction of ventricles. 65. Cardiovascular System Functions: Regulates blood supply, generates blood pressure, routes blood, and ensures one-way blood flow. 66. Sinoatrial (SA) Node: The heart's natural pacemaker initiating each heartbeat. 67. Atrioventricular (AV) Node: Delays the electrical impulse from the atria to the ventricles. 68. Bundle of His (AV Bundle): Transmits the impulse from the AV node to the ventricles. 69. Bundle Branches and Purkinje Fibers: Distribute the impulse throughout the ventricles for contraction. 70. Rhythmicity: The heart's ability to beat regularly. 71. Repolarization Phase: K+ channels open, Ca2+ channels close. 72. Coronary Artery Disease: A condition characterized by the narrowing of coronary arteries. 73. Hypertension: High blood pressure affecting cardiovascular health. 74. Heart Failure: A condition where the heart cannot pump sufficiently. 75. Composition of Blood: Red blood cells, white blood cells, platelets, and plasma. 76. Hemoglobin: Protein in red blood cells that carries oxygen. 77. Regulatory Mechanisms: How hormones like adrenaline and the nervous system influence heart function.