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140) The anterior view of the heart is dominated by which chambers? (Module 18.4A) A) right atrium and right ventricle B) left atrium and left ventricle
A
156) Why does tetany not occur in cardiac muscle? (Module 18.11A) B) Tetany does not occur because the gap junctions in cardiac muscle prevent the sustained contraction. C) Tetany does not occur because cardiac muscle has a long refractory period that continues until relaxation is well under way so summation cannot occur, and thus tetany cannot occur.
C
158) Define autorhythmicity. (Module 18.12A) B) Autorhythmicity is the ability of the heart to contract with hormonal stimulation. C) Autorhythmicity is the ability of the heart to contract without neural or hormonal stimulation.
C
154) List the phases of the cardiac cycle. (Module 18.10A) D) atrial systole, atrial diastole, ventricular systole, ventricular diastole E) atrial systole, ventricular systole, ventricular diastole
D
160) Define electrocardiogram. (Module 18.13A) D) An electrocardiogram is a recording of the electrical activity of the heart. E) An electrocardiogram is a recording of the contractile activity of the heart.
D
135) Define mediastinum. (Module 18.2A) A) The mediastinum is the region that contains each lung. B) The mediastinum is the region between the two pleural cavities that contains the heart, along with the great vessels, thymus, esophagus, and trachea.
B
134) Compare the volume of blood each circuit receives from contraction of the ventricles. (Module 18.1D) C) Both circuits receive the same volume of blood. D) The systemic circuit receives three times as much blood as the pulmonary circuit.
C
141) Which structures collect blood from the myocardium, and into which heart chamber does this blood flow? (Module 18.4B) C) Coronary veins collect blood from the myocardium and carry it to the right atrium. D) Coronary veins collect blood from the myocardium and carry it to the left atrium.
C
148) What do semilunar valves prevent? (Module 18.7C) B) Semilunar valves prevent backflow of blood into the atria. C) Semilunar valves prevent backflow of blood into the ventricles.
C
132) Compare the base of the heart with the apex. (Module 18.1B) A) The base of the heart is the inferior portion where the largest veins and arteries are attached. The apex of the heart is located on the superior aspect of the heart. B) The base of the heart is the superior portion where the largest veins and arteries are attached. The apex of the heart is located on the inferior aspect of the heart.
B
131) Describe the location and position of the heart. (Module 18.1A) A) The heart is located near the anterior chest wall, directly behind the sternum. B) The heart is located near the posterior chest wall, directly beside the vertebral column.
A
137) Why can cardiac tamponade be a life-threatening condition? (Module 18.2C) A) Cardiac tamponade can be life-threatening because accumulating fluid in the pericardial cavity restricts heart movement. B) Cardiac tamponade can be life-threatening because accumulating fluid in the mediastinum restricts heart movement.
A
149) Compare arteriosclerosis with atherosclerosis. (Module 18.8A) A) Arteriosclerosis is any thickening and toughening of arterial walls; atherosclerosis is a type of arteriosclerosis characterized by changes in the endothelial lining and the formation of fatty deposits (plaque) in the tunica media. B) Arteriosclerosis is a type of atherosclerosis characterized by changes in the endothelial lining and the formation of fatty deposits (plaque) in the tunica media. Atherosclerosis is any thickening and toughening of arterial walls.
A
153) Compare the duration of atrial and ventricular systole at a representative heart rate of 75 bpm. (Module 18.9C) A) Atrial systole has a duration of 100 msec, and ventricular systole has a duration of 270 msec. B) Atrial systole has a duration of 270 msec, and ventricular systole has a duration of 100 msec.
A
164) Describe the sites and actions of the cardioinhibitory and cardioacceleratory centers. (Module 18.14B) A) The cardioacceleratory center in the medulla oblongata activates sympathetic neurons to increase heart rate; the cardioinhibitory center in the medulla oblongata activates parasympathetic neurons that slow heart rate. B) The cardioacceleratory center in the medulla oblongata activates parasympathetic neurons to increase heart rate; the cardioinhibitory center in the medulla oblongata activates sympathetic neurons that slow heart rate. .
A
142) Describe the areas of the heart supplied by the right and left coronary arteries. (Module 18.5A) A) The right coronary artery supplies blood to left atrium and portions of both ventricles. The left coronary artery supplies blood to the right atrium, the conducting system, and interventricular septum. B) The right coronary artery supplies blood to the right atrium, portions of both ventricles, and the conducting system. The left coronary artery supplies blood to the left ventricle, left atrium, and interventricular septum.
B
145) Why is the left ventricle more muscular than the right ventricle? (Module 18.6A) A) The left ventricle is supplied with more coronary vasculature so it hypertrophies over time, whereas the right ventricle receives less blood so it atrophies over time. B) The left ventricle must generate enough force to propel blood through the systemic circuit, whereas the right ventricle must generate only enough force to propel blood the short distance from the heart to the lungs in the pulmonary circuit.
B
155) What are the two phases of ventricular systole? (Module 18.10B) A) left ventricular systole and right ventricular systole B) isovolumetric contraction and ventricular ejection
B
159) If the cells of the SA node failed to function, how would the heart rate be affected? (Module 18.12B) A) The heart would beat faster because the AV node would be the pacemaker. B) The heart would beat slower because the AV node would be the pacemaker.
B
162) Why is ventricular fibrillation fatal? (Module 18.13C) A) Ventricular fibrillation is fatal because the ventricles quiver and do not relax long enough to be filled with blood by the atria. B) Ventricular fibrillation is fatal because the ventricles quiver and do not pump blood to the systemic circulation. decreases.
B
136) Describe the heart's location in the body. (Module 18.2B) D) The heart is surrounded by the pericardium in the anterior mediastinum, deep to the sternum and superior to the diaphragm. E) The heart is surrounded by the pericardium in the posterior mediastinum, deep to the lungs and superior to the diaphragm.
D
139) Why is it important that cardiac tissue contain many mitochondria and capillaries? (Module 18.3C) D) Cardiac tissue is metabolically active and dependent on mitochondrial activity to use aerobic respiration to generate ATP and capillaries provide the oxygen and nutrients for this process. E) Cardiac tissue is metabolically active and dependent on the mitochondrial activity for the breakdown of fatty acids during beta-oxidation and the capillaries provide the fatty acids for this process.
D
143) Compare the anterior cardiac veins to the posterior vein of the left ventricle. (Module 18.5B) D) The anterior cardiac veins drain the anterior surface of the right ventricle and empty into the right atrium; the posterior vein of left ventricle drains the area supplied by the circumflex artery (posterior surface of the left ventricle). E) The anterior cardiac veins drain the right atrium and right ventricle and empty into the right atrium; the posterior vein of left ventricle drains the left atrium and left ventricle.
D
147) Define cardiac regurgitation. (Module 18.7A) D) Cardiac regurgitation is the backflow of blood into the atria when the ventricles contract. E) Cardiac regurgitation is the backflow of blood into the ventricles from the outflow vessels when the ventricles relax.
D
150) What is coronary ischemia? (Module 18.8B) D) Coronary ischemia is a condition in which the blood supply of the coronary arteries is reduced. E) Coronary ischemia is an irregular heart rhythm caused by an ectopic pacemaker.
D
152) Give the alternate terms for heart contraction and heart relaxation. (Module 18.9B) D) The alternate term for heart contraction is systole and the alternate term for heart relaxation is diastole. E) The alternate term for heart contraction is diastole and the alternate term for heart relaxation is systole.
D
133) Name the four chambers of the heart. (Module 18.1C) D) superior pulmonary chamber, inferior pulmonary chamber, superior systemic chamber, inferior systemic chamber E) left atrium, left ventricle, right atrium, right ventricle
E
138) From superficial to deep, name the layers of the heart wall. (Module 18.3A) C) myocardium, pericardium, endocardium D) pericardium, endocardium, myocardium E) pericardium, myocardium, endocardium
E
151) Define cardiac cycle. (Module 18.9A) D) Cardiac cycle is time it takes the entire volume of blood to cycle through the heart. E) Cardiac cycle is the period between the start of one heartbeat and the beginning of the next.
E
157) List the three stages of an action potential in a cardiac muscle cell. (Module 18.11B) D) rapid depolarization, repolarization, hyperpolarization E) rapid depolarization, plateau, and repolarization
E
163) Compare bradycardia with tachycardia. (Module 18.14A) D) Bradycardia is a heart rate below 80 beats per minute and tachycardia is a heart rate above 120 beats per minute . E) Bradycardia is a heart rate below 60 beats per minute and tachycardia is a heart rate above 100 beats per minute.
E
