BIO 207: Vertebrate Physiology - Portfolio – Muscle Physiology Assignment

Internal Code: MAS3375

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Questions: 1. Answer each of the following related to the anatomy of the heart. A. What is the pericardium? B. Explain the structural differences between the cuspid and semilunar valves. C. Briefly explain the blood supply and drainage of the heart muscle proper. D. Trace the flow of blood through the heart beginning with deoxygenated blood returning to the heart from the head and neck via the superior vena cava. Include in your description heart chambers, heart valves, and major blood vessels/organs encountered along the way. The blood should ultimately exit the heart and enter the systemic circulation as oxygenated blood directed toward the head and neck region. 2. Answer each of the following questions related to the electrical activity and intrinsic conduction system of the heart. A. What is the pacemaker of the heart? Explain. B. Label the diagram below and describe the conduction system of the heart, including theb origin, sequence and relative speed of conduction through each of its components. Why does the speed of conduction vary? C. Explain the cardiac action potentials generated in autorhythmic and contractile cells, including ionic events, relevant structural features, and how these two action potentials are coupled to insure contraction as a unit. Diagramatic representations of the action potentials may be helpful. What is the nature and function of the nervous innervation of the mammalian heart? 3. Diagram and characterize the following events (diastole and systole, ECG, heart sounds, aortic pressure, pressure changes in the atria, pressure and volume changes in the ventricles) as they occur during a single cardiac cycle. The cardiac cycle is often divided into several phases, ventricular filling, atrial contraction, isovolumetric contraction, ventricular systole, and isovolumetric relaxation. Explain each of these phases as part of your characterization. 4. Answer each of the following questions related to cardiac output. A. Define cardiac output. B. Define stroke volume and discuss the factors that influence the stroke volume of the heart. C. Explain how each of the following conditions would influence cardiac output. 5. Using the diagram below of a blood pressure wave recorded from the radial artery, identify and explain each of the following: A. systolic blood pressure B. diastolic blood pressre C. dicrotic notch D. mean arterial pressure E. pulse pressure 6. Explain how blood pressure is normally measured, and why blood pressure is a good indicator of overall cardiovascular health. 7. Blood pressure is affected by several factors, including cardiac output, total peripheral resistance, vessel elasticity and blood volume. In the table below briefly explain how each of these factors influences blood pressure. 8. Blood pressure regulation can be short-term or long-term. Short-term mechanisms regulate vessel diameter, heart rate and heart contractility. Describe the physiological response to a short-term decrease in blood pressure (hypotension). 9. Long-term mechanisms of blood pressure regulation involve the regulation of blood volume. A decrease in blood pressure resulting from hemorrhage, accident with severe bleeding, or blood donation would stimulate these long term regulatory mechanisms. The list below represents the steps involved in this mechanism of long-term blood pressure regulation. Place them in the correct order of occurrence beginning with 1 as the first event and continuing in numerical order.

• movement of water from the kidhey tubules into the blood
• lung enzyme converts angiotensin I to angiotensin II
• increase in blood volume
• release of the enzyme renin by the juxtaglomerular cells in the kidney
• decreased blood pressure resulting from hemorrhage, accident, or blood donation
• increase in blood pressure
• aldosterone released from the adrenal cortex
• angiotensinogen (inactive plasma protein) converted to angiotensin I
• vasoconstriction leading to increase in blood pressure
• increased reabsorption of Na + from the distal convoluted tubules

10. Another long-term mechanism of blood pressure regulation occurs following severe dehydration (excessive sweating, diarrhea, or excessive urine outflow). Explain this mechanism, including the initial short-term response followed by the long-term response.