Answer Happy

35. What is the significance of the prolonged action potential in cardiac muscle cells? 36. Compare and contras excitarion-contraction coopling in cardiac ves skeletal muscle. 37. Describe the mechanism of Ca2+ release in cardiac muscle. 38. What determines the amount of Ca24 release in cardiac muscle? 39. What is the significance of increased Ca2+ induced Ca24 relcase in cardiac muscle? 40. What is the cardiac eycle? 41. Define systole and diastole. 42. Describe the phases of the cardiac cycle. 43. What is the contribution of atrial contraction to ventricular filling? 44. Define the following tenms: end diastolic volume, stroke volume, ejcction fraction and end systolic volume. 45. Be able to identify the events during each phase of the cardiac cycle using a pressure-volume loop. 46. At what points in the cardiac cycle are all the heart valves closed? 47. Be able to identify the points in the cardiac cycle when the valves are open and closed. 48. Why does isovolumic (or isovolumetric) contraction occur? 49. Define cardiac output. 50. What factors determine cardiac output. 51. Describe the relationship between cardiac output, heart rate, and stroke volume (how do changes in SV and HR influence CO?). 52. What two mechanisms cause SV to increase during exercise? 53. What is preload? 54. What is the Frank-Starling Law of the heart? 55. What determines the preload of the heart? 56. Define venous return. 57. What determines filling time? 58. Describe how each of the following would affect the preload of the heart: changes in HR, VR and blood volume. 59. How does an increase in preload effect each of the following: EDV,SV, ESV, CO and EF? 60. Define contractility. 61. What causes an increase in contractility of the heart? 62. How does an increase in contractility effect each of the following: EDV, SV, ESV, CO and EF? 63. What is the afterload of the heart? 64. How is the heart effected by an increased afferload? 65. What are the effects of sympathetic and parasympathetic input on the heart? 66. What are the effects of catecholamines on the heart?