MT3 - Guided Reading - Thorax (Part 1-2)
22) Which of the following is true of the contraction of the heart? A) Cardiac contractions are coordinated by specialized conductive cardiac muscle fibers. B) The muscle obtains the beat from the pacemaker region exclusively. C) The ventricles contract first, followed by the atria. D) The contractions do not occur in any specific repeatable sequence each time. E) None of the above are true.
A) Cardiac contractions are coordinated by specialized conductive cardiac muscle fibers.
2) Which of the following is true of the coronary arteries? A) They originate at the base of the aorta and are the first branch off this vessel. B) They branch off the pulmonary veins. C) They open and close in pulsation with the contraction and relaxation of the heart ventricles. D) Together they supply part of the heart muscle with oxygen. E) None of the above are true.
A) They originate at the base of the aorta and are the first branch off this vessel.
5) At rest the heart rate is usually ________ by parasympathetic control. A) decreased B) shut down C) unchanged D) increased E) none of the above
A) decreased
6) Cardiac muscle differs from other muscle tissue in A) having fibers connected to one another at intercalated discs. B) having larger sized fibers than other striated muscles. C) having fewer mitochondria. D) having striations. E) no ways; it is not unusual.
A) having fibers connected to one another at intercalated discs.
14) The moderator band is located in the A) right ventricle. B) left ventricle. C) right atrium. D) interventricular sulcus. E) left atrium.
A) right ventricle.
1) The left ventricle A) sends blood out through the aortic semilunar valve to the systemic circulation. B) pumps blood out of the heart to the pulmonary circuit. C) receives blood from the left atrium through the tricuspid valve. D) has thinner muscular walls than does the right ventricle. E) does all of the above.
A) sends blood out through the aortic semilunar valve to the systemic circulation.
19) The heart has the unique ability to change its workload. On average the heart can pump between ________ and ________ liters of blood per minute. A) 1; 3 B) 5; 30 C) 10; 20 D) 5; 50 E) 2; 20
B) 5; 30
3) How would the heart rate be affected if there were a blockage of the AV node? A) The heart rate would be unaffected. B) The electrical stimuli from the SA node would be normal, but the rate of contraction would slow or be irregular. C) The heart rate would slow dramatically, and become extremely irregular, contracting only when the ventricles became overfilled. D) The heart would cease to contract. E) The heart rate would increase.
B) The electrical stimuli from the SA node would be normal, but the rate of contraction would slow or be irregular.
24) Which of the following is an incorrect association? A) atrioventricular tricuspid valve B) atrioventricular aortic valve C) semilunar pulmonary valve D) atrioventricular mitral valve E) None of the above are incorrect.
B) atrioventricular aortic valve
16) Functions of the endocardium include A) forming the atria and ventricles of the heart. B) covering the inner surfaces of the heart, including the valves. C) covering the outer surface of the heart. D) covering the interatrial septum. E) all of the above.
B) covering the inner surfaces of the heart, including the valves.
16) Cardiac muscle cells do not need ________ to contract. A) sodium B) nervous stimulation C) ATP D) calcium E) potassium
B) nervous stimulation
8) The tough structure that surrounds the heart and helps prevent overfilling is the A) epicardium. B) pericardial sac. C) pleural cavity. D) aorta. E) mediastinum.
B) pericardial sac.
7) The right ventricle pumps blood into the A) vena cava. B) pulmonary arteries. C) aorta. D) pulmonary semilunar valves. E) pulmonary veins.
B) pulmonary arteries.
3) The left atrium receives blood from the A) pulmonary trunk. B) pulmonary veins. C) aorta. D) mitral valve. E) coronary arteries.
B) pulmonary veins.
7) The phase of the cardiac cycle during which each chamber contracts and pushes blood into an adjacent chamber is A) relaxation. B) systole. C) diastole. D) ejection. E) none of the above.
B) systole.
11) Blood travels from the right atrium to the right ventricle through the A) semilunar valve. B) tricuspid valve. C) fossa ovalis. D) conus arteriosus. E) mitral valve.
B) tricuspid valve.
14) The heart wall is composed of ________ layers of tissues. A) 1 B) 2 C) 3 D) 4 E) 5
C) 3
13) Pacemaker cells depolarize about A) 40-50 times per minute. B) 120- 140 times per minute. C) 80- 100 times per minute. D) 60- 70 times per minute. E) None of the above apply to pacemaker cell depolarization.
C) 80- 100 times per minute.
18) Blood is supplied to the muscle of the heart through the A) cardiac sinus. B) pulmonary arteries. C) coronary arteries. D) interventricular septum. E) conus arteriosus.
C) coronary arteries.
17) The QRS complex of the electrocardiogram occurs when A) repolarization of the ventricles occurs. B) repolarization of the atria occurs. C) depolarization of the ventricles occurs. D) the atria depolarize. E) none of the above occurs.
C) depolarization of the ventricles occurs.
2) Externally the posterior and inferior portions of the left ventricle form the A) sternocostal surface. B) right border. C) diaphragmatic surface. D) superior border. E) left border.
C) diaphragmatic surface.
5) During one cardiac cycle the heart spends most of its time in A) fibrillation. B) contraction. C) diastole. D) systole. E) none of the above states.
C) diastole.
12) The visceral pericardium is also called the A) pericardial sac. B) fibrous pericardium. C) epicardium. D) pericardial cavity. E) parietal pericardium.
C) epicardium.
21) One of the major differences between skeletal muscle and cardiac muscle is that cardiac muscle A) has myosin and actin. B) needs Ca2+ to contract. C) lacks a triad. D) is striated. E) has the attributes of A and B.
C) lacks a triad.
4) Which of the following is supplied with blood by the left coronary artery? A) the conducting system B) right atrium C) left atrium D) posterior heart wall E) right ventricle
C) left atrium
10) The connective tissues of the heart A) consist only of many dense collagen fibers. B) do not join the muscle fibers to the fibrous skeleton of the heart. C) provide a strong fibrous cross linkage system wrapping adjacent muscle cells together. D) have the attributes of A and C. E) have none of the above attributes.
C) provide a strong fibrous cross- linkage system wrapping adjacent muscle cells together.
9) The coronary artery found in the coronary sulcus is (the) A) circumflex artery. B) posterior interventricular artery. C) right coronary artery. D) LAD. E) none of the above
C) right coronary artery.
4) Analysis of an ECG can reveal A) damage to the coronary vessels. B) the condition of the conducting system. C) the sequence of the valves opening and closing. D) the volume of blood passing through the heart. E) none of the above.
C) the sequence of the valves opening and closing.
11) Which of the following conditions would be caused if the amount of blood entering the ascending aorta with each contraction of the heart were increased? A) The atrioventricular valves would not close. B) The amount of blood sent to the lungs for oxygenation would decrease. C) Stimulation by the sympathetic nervous system would accompany this change. D) The amount of blood entering the right atrium of the heart would have been increased. E) The heartbeat would be speeded up by the parasympathetic nervous system.
D) The amount of blood entering the right atrium of the heart would have been increased.
23) In terms of time, at rest one cardiac cycle lasts A) 5 seconds. B) about a half second. C) about 1.5 seconds. D) a little under 1 second. E) none of the above amounts of time.
D) a little under 1 second.
17) Cardiac muscle cells obtain energy almost exclusively through A) protein stores. B) the Krebs cycle. C) anaerobic pathways. D) aerobic respiration. E) glycolysis.
D) aerobic respiration.
10) The most important factor in ensuring that blood moves in correct order through the heart is (the) A) strength of the contraction of the different parts of the myocardium. B) location of the main electrical conduction node. C) coordination of the timing of atrial and ventricular systole. D) amount of blood in each of the chambers at any given time. E) none of the above.
D) amount of blood in each of the chambers at any given time.
24) Which of the following empties directly into the right atrium? A) small cardiac vein B) great cardiac vein C) middle cardiac vein D) anterior cardiac veins E) none of the above
D) anterior cardiac veins
20) The upper right edge of the heart is the A) apex. B) anterior surface. C) sternocostal surface. D) base. E) pulmonary surface.
D) base.
23) During their period of systole, the inner volume of the atrial chambers A) does not change. B) increases, as does the volume in the auricles. C) remains the same, but the auricles enlarge rapidly. D) decreases. E) does none of the above.
D) decreases.
15) The chambers of the heart fill during A) systole. B) atrial systole. C) maximum contraction. D) diastole. E) none of the above.
D) diastole.
12) Papillary muscles receive a signal to contract from (the) A) Purkinje fibers. B) AV node. C) bundle branches. D) moderator band. E) none of the above.
D) moderator band.
22) Structures in the heart that establish the rate of contraction are called A) the chordae tendineae. B) conducting fibers. C) Purkinje fibers. D) nodes. E) none of the above.
D) nodes.
25) Prominent muscular ridges that run along the inner surface of the auricle and across the adjacent atrial wall are the A) chordae tendineae. B) papillary muscles. C) foramen ovale. D) pectinate muscles. E) trabeculae carneae.
D) pectinate muscles.
15) If a small blood clot passes through the heart and heart vessels, where is it most likely to cause damage if it becomes immobilized? A) the aorta B) the left ventricle C) the right atrial chamber D) the left coronary artery E) Severe damage could occur if a small blood clot became immobilized at any of these positions.
D) the left coronary artery
8) The most serious place for a blockage of a coronary artery is A) the circumflex branch of the left coronary artery. B) the left coronary artery. C) the posterior interventricular artery. D) the right marginal branch of the right coronary artery. E) none of the above.
D) the right marginal branch of the right coronary artery.
9) The contraction of any one cardiac muscle fiber A) will trigger an all-or- none response in all other cardiac fibers. B) will stimulate the electrical conduction system of the heart. C) will cause the rate of heart muscle contraction to increase. D) will cause the contraction of several others. E) will do none of the above.
D) will cause the contraction of several others.
1) Grooves on the external surface of the heart that divide the right and left ventricles include the A) lateral sulcus. B) anterior interventricular sulcus. C) coronary fissure. D) posterior interventricular sulcus. E) B and D.
E) B and D.
21) The grooves on the outside of the heart contain A) fat. B) coronary arteries. C) anastomoses. D) cardiac veins. E) all of the above.
E) all of the above
6) Which of the following valves is assisted in functioning by the papillary muscles? A) right atrioventricular valve B) tricuspid valve C) left atrioventricular valve D) mitral valve E) all of the above
E) all of the above
13) Nodal activity of the heart may be influenced or modified by A) hormones secreted by the lungs. B) the sympathetic component of the autonomic nervous system. C) the parasympathetic component of the autonomic nervous system. D) either the SA node or the AV node, but no other system. E) both B and C.
E) both B and C.
25) The fibrous skeleton of the heart functions to A) maintain the shape of the heart. B) strengthen and help prevent overexpansion of the heart. C) provide an anchor for the heart valves. D) help distribute the force of contraction of the heart. E) do all of the above.
E) do all of the above.
19) The reinforcing layer of the pericardium is the ________ layer. A) parietal B) visceral C) epicardial D) sutural E) fibrous
E) fibrous
18) The main pacemaker region of the heart is A) able to cause the muscle to begin to contract at the apex. B) able to cause the atria and ventricles to contract simultaneously. C) in the interventricular septum. D) electrically active nodal tissue located in the wall of the left ventricle. E) in the wall of the right atrium.
E) in the wall of the right atrium.
20) Most of the thickness of the heart wall is the A) connective tissue. B) endocardium C) parietal and visceral layers of the epicardium. D) fibrous pericardium. E) myocardium.
E) myocardium.
