Cardiovascular Physiology Exam Questions and Answers Latest Update Graded A+

Cardiovascular Physiology Exam Questions and Answers Latest Update Graded A+ Choose the correct order of structures that blood would contact as it traveled from the left atrium through the blood vessels and back to the right atrium. 1)abdominal aorta 2)ascending arteries 3)inferior vena cava 4)hepatic artery 5)superior vena cava 6)left ventricle 7)ascending veins - Answers Left ventricle, abdominal aorta, hepatic artery, ascending veins, inferior vena cava Which of the following is the correct description of a myocardial infarction and what it is caused by? -A region of heart muscle dies due to a lack of glucose supply. -A region of heart muscle dies due to a lack of blood supply. -A region of muscle becomes inactive due to a lack of neuronal stimulation. -A region of heart muscle becomes overly active. - Answers A region of heart muscle dies due to a lack of blood supply. How does administration of nitroglycerine help someone that might be suffering from a myocardial infarction? -Nitroglycerine will dilate the coronary vessels, which will increase blood flow to the heart muscle. -Nitroglycerine will constrict the coronary vessels, which will increase blood flow to the heart muscle. -Nitroglycerine will dilate the coronary vessels, which will decrease blood flow to the heart muscle. -Nitroglycerine will constrict the coronary vessels, which will decrease blood flow to the heart muscle. - Answers Nitroglycerine will dilate the coronary vessels, which will increase blood flow to the heart muscle. Although the lab results from Walter's blood work will take an hour, the ER physician is certain that Walter has had a myocardial infarction. How did he reach this diagnosis without knowing the results of the blood work? -The ECG of Walter's heart showed the signs of a myocardial infarction. -Walter was very clammy, pale, and incoherent. -Walter expressed pain and tightness in his chest. -Walter had a bluish tint to his skin when he came in to the ER - Answers The ECG of Walter's heart showed the signs of a myocardial infarction. What would a balloon angioplasty do to the resistance in Walter's affected coronary vessel and how would this improve his condition? - Answers decrease; increased blood flow to the myocardium As blood flows away from the heart, how does overall blood pressure in vessels change? Why? - Answers Blood pressure decreases, because of the effects of friction between the vessel walls and the moving blood. If the radius of a tube decreases by half, what would happen to the resistance to fluid flow? - Answers Resistance would increase 16 times. Which of these would cause an increase in blood flow through a vessel? -Increased blood viscosity -Vasodilation -Vasoconstriction -Increased vessel length - Answers Vasodilation What is an advantage to the longer duration of cardiac action potential compared to the skeletal muscle action potential? - Answers The longer duration prevents tetanic contraction, which ensures that the heart chambers will relax and refill with blood before the next contraction. What is the role of heart valves? - Answers Heart valves ensure one-way flow of blood through the heart chambers. In skeletal muscle cells, action potentials cause the release of calcium from the SR by directly opening SR voltage-gated calcium channels. What causes the release of calcium from the SR in cardiac muscle cells? - Answers Influx of extracellular calcium ions opens ryanodine receptors allowing Ca2+ to flow out of the SR. Calcium ions are removed from the sarcoplasm of the cardiac cell by the action of the sarcoplasmic reticulum (SR) Ca2+-ATPase pump and which other mechanism? - Answers sodium-calcium exchanger on the sarcolemma In a cardiac autorhythmic cell, which ion is responsible for the increase in membrane potential from threshold during an action potential? - Answers Ca2+ What structure in the intrinsic cardiac conduction system determines heart rate? - Answers the sinoatrial (SA) node In contrast to a skeletal muscle cell action potential, why does the action potential for a cardiac muscle cell contain a "plateau" phase? - Answers Cardiac muscle cells contain slow Ca2+ channels in their sarcolemma that continue to allow influx of Ca2+ ions after Na+ channels are inactivated. Why does a graph of the membrane potential of living pacemaker cells never demonstrate a flat line? - Answers Hyperpolarization of pacemaker cells triggers the opening of slow Na+ channels and starts a new slow depolarization phase. What is the role of the atrioventricular bundle? - Answers The atrioventricular bundle provides the only pathway for electrical signals to pass from the atria to the ventricles. What are If channels responsible for in cardiac autorhythmic cells? - Answers the pacemaker potential The term myogenic indicates that the heart muscle is the source of - Answers the electrical signal that triggers heart contraction. The rapid depolarization phase of the action potentials of myocardial contractile cells is due to which ion(s)? - Answers Na+ only During the plateau phase of the action potentials of myocardial contractile cells, which ion(s), including those at decreased levels, is/are crossing the membrane? - Answers Both Ca2+ and K+ The action potentials of myocardial autorhythmic cells, are due to a combination of increasing Ca2+ ________ and decreasing K+________. - Answers influx, efflux The end of the plateau phase is due to the ________ of Ca2+ channels and ________ of K+ channels. - Answers closing; opening A typical action potential of a myocardial contractile cell lasts ________ millisecond(s). - Answers at least 200 The importance of the plateau phase of the action potential of myocardial cells is in - Answers preventing tetanus. Myocardial cells can generate action potentials spontaneously because they have - Answers unstable ion channels. If channels are permeable to - Answers Na+ and K+