Heart MC practice #1
A blood clot in the circumflex artery would cause a myocardial infarction in part of the A) walls of the left atrium and posterior left ventricle. B) anterior walls of the left and right ventricles, and the interventricular septum. C) posterior walls of the left and right ventricles. D) lateral walls of the right atrium and right ventricle.
A
A needle being inserted into the heart would travel through the layers of the heart wall and coverings in which order, beginning on the outside? A) fibrous pericardium, parietal pericardium, visceral pericardium, myocardium, endocardium B) parietal pericardium, fibrous pericardium, visceral pericardium, myocardium, endocardium C) endocardium, myocardium, fibrous pericardium, parietal pericardium, visceral pericardium D) visceral pericardium, parietal pericardium, fibrous pericardium, endocardium, myocardium
A
A point where two arteries connect and combine their blood flow is called a(n) A) anastomosis. B) infarction. C) divergence. D) aneurysm.
A
Calcium is needed for contraction in both skeletal muscle and cardiac muscle. However there are some differences in where it comes from and what it does. Which of these choices correctly describes how calcium works in cardiac muscle cells? A) Extracellular Ca2+ diffuses into the cardiac muscle cells, binds to Ca2+ channels in the sarcoplasmic reticulum and causes Ca2+ release into the cytosol. B) Extracellular Ca2+ diffuses into the cardiac muscle cells, binds to troponin and initiates contraction. C) Ca2+ from the sarcoplasmic reticulum diffuses out of the cell, causing the plateau phase of the action potential. D) Ca2+ from the sarcoplasmic reticulum diffuses out of the cell, causing repolarization.
A
Energy for contraction of myocardial cells comes primarily from A) aerobic respiration in the mitochondria. B) anaerobic respiration in the cytosol. C) glycolysis in the cytosol. D) ATP that is stored while the heart is not contracting.
A
In an ECG taken from a person who has no SA node activity, which component will not appear? A) P wave B) QRS complex C) ST segment D) T wave
A
In response to exercise, the heart would be called upon to _____ the amount of blood pumped, and this would be initiated by signals from ______ fibers. A) increase; sympathetic B) increase; parasympathetic C) decrease; sympathetic D) decrease; parasympathetic
A
In the cardiac conduction system, junctional fibers connect the A) atrial syncytium to the AV node. B) AV node to the AV bundle. C) SA node to the Purkinje fibers. D) AV bundle branches to the Purkinje fibers.
A
In which choice are the components of the heart placed in correct order of decreasing intrinsic rhythm? A) SA node, AV node, Purkinje cells B) SA node, Purkinje cells, AV node C) AV node, SA node, Purkinje cells D) Purkinje cells, AV node, SA node
A
Intercalated discs include these structures: A) gap junctions, desmosomes, interdigitating folds B) gap junctions, tight junctions, t-tubules C) gap junctions, desmosomes, t-tubules D) sarcoplasmic reticulum, interdigitating folds
A
The "skeleton" of the heart A) provides attachment for the heart valves and cardiac muscle B) is made of fibrocartilage C) provides internal support for the cardiac chambers D) is also called the fibrous pericardium
A
The action of acetylcholine after binding to muscarinic receptors on the SA node is to A) open K+ channels, causing hyperpolarization and a decreased rate of spontaneous depolarization B) close K+ channels, causing depolarization and and increased rate of spontaneous depolarization C) open Ca2+ channels, causing increased Ca2+ entry and a stronger contraction D) close Ca2+ channels, causing decreased Ca2+ entry and a faster rate of spontaneous depolarization
A
The amount of blood ejected from the heart in one minute is called the A) cardiac output B) end diastolic volume C) end systolic volume D) stroke volume
A
The amount of blood in the ventricles just before they contract is called the A) end diastolic volume B) end systolic volume C) stroke volume D) cardiac output
A
The atria are electrically isolated from the ventricles by the A) fibrous skeleton B) AV bundle C) visceral pericardium D) Purkinje fibers
A
The atrioventricular valves open when pressure in the A) atria is greater than pressure in the ventricles. B) ventricles is greater than pressure in the arteries. C) arteries is greater than pressure in the ventricles. D) ventricles is greater than pressure in the atria.
A
The cells of the heart's normal pacemaker A) spontaneously generate electrical signals about 70 to 80 times per minute. B) are located in the interventricular septum. C) generate electrical signals only when stimulated by sympathetic fibers. D) are not in contact with other cells of the heart.
A
The coronary sinus is a(n) ______ located in the ________. A) vein; posterior atrioventricular sulcus B) vein; posterior interventricular sulcus C) artery; anterior atrioventricular sulcus D) artery; interatrial septum
A
The function of the pericardial fluid is to A) reduce friction between the pericardial membranes. B) lubricate the heart valves. C) replace any blood that is lost. D) provide oxygen and nutrients to the endocardium.
A
The plateau phase of the cardiac contractile cell action potential is caused by A) Ca2+ inflow B) Cl- inflow C) K+ outflow D) Na+ outflow
A
The right ventricle of the heart acts as a pump for the A) pulmonary circulation. B) systemic circulation. C) coronary circulation. D) hepatic portal circulation.
A
Which component of a myocardial cell allows it to electrically stimulate adjoining cells? A) gap junctions B) t-tubules C) desmosomes D) sarcoplasmic reticulum
A
Which ionic imbalance would decrease the strength of cardiac muscle contraction? A) hypocalcemia B) hypercalcemia C) hypokalemia D) hyponatremia
A
Which of the following is not a positive chronotrope? A) acetylcholine B) epinephrine C) thyroid hormone D) caffeine
A
All cardiac veins empty into the ______, which then empties into the ______. A) coronary sinus; left atrium B) coronary sinus; right atrium C) great cardiac vein; right atrium D) great cardiac vein; left atrium
B
An auricle is A) a valve located in a blood vessel B) an extension of the atrial wall C) part of a heart valve D) a blood vessel that carries blood away f
B
An electrocardiogram actually records A) the contraction and relaxation of the myocardium B) electrical changes that occur in the myocardial cells. C) blood flow through the heart. D) changes in pressure in the left ventricle.
B
An obstruction in the pulmonary trunk would prevent blood from A) being distributed to the systemic circulation B) picking up oxygen in the lungs C) getting into the right atrium D) leaving the left ventricle
B
Any factor that alters heart rate is called A) a chemotrope B) a chronotrope C) an inotrope D) an isotope
B
Blood from the pulmonary veins enters which heart chamber? A) right atrium B) left atrium C) right ventricle D) left ventricle
B
Conduction of the cardiac impulse is slowed as it passes through the AV node. This allows time for the A) ventricles to start contracting before the atria finish contracting. B) atria to contract completely before the ventricles start to contract. C) SA node to catch up. D) last ventricular contraction to finish.
B
During ventricular diastole A) pressure in the atria exceeds pressure in the ventricles and the atrioventricular valves open B) pressure in the ventricles eventually exceeds pressure in the arteries and the semilunar valves open. C) the atria contract and pump blood into the ventricles D) no blood enters the arteries
B
If the SA node is damaged, which part of the heart is most likely to take over as a pacemaker? A) atrial myocardial cells B) AV nodal cells C) Purkinje fibers D) ventricular myocardial cells
B
In which choice are the components of the cardiac conduction system listed in the correct sequence? A) SA node, AV bundle, AV node, Purkinje fibers B) SA node, AV node, AV bundle, Purkinje fibers C) AV node, AV bundle, SA node, Purkinje fibers D) AV node, SA node, Purkinje fibers, AV bundle
B
Joe's cardiac output at rest is 5 L/min. When he is exercising strenuously it is 20 L/min. What is Joe's cardiac reserve? A) 4 L/min B) 15 L/min C) 25 L/min D) 100 L/min
B
Of the amount of blood entering the ventricles before they contract A) about 70% comes in during atrial contraction. B) about 70% comes in before atrial contraction. C) 100% comes in during atrial contraction. D) 30% comes in during atrial contraction and 70% comes in during ventricular contraction.
B
Slowing the heart while holding the rate of venous return (ml/min) constant would cause A) decreased cardiac output B) increased cardiac output C) no change in cardiac output, because heart rate is not increased D) no change in cardiac output, because stroke volume is not increased
B
The aorta and pulmonary trunk extend from the heart at its A) apex. B) base. C) interventricular sulcus. D) atrioventricular sulcus.
B
The chordae tendineae A) attach the semilunar valves directly to the heart wall B) prevent the atrioventricular valve cusps from prolapsing into the atria during ventricular systole C) open the atrioventricular valves during ventricular systole D) attach the heart to the pericardium
B
The normal rate of spontaneous depolarization of the AV node is A) 20 - 40 per minute B) 40 - 60 per minute C) 70 - 80 per minute D) over 100 per minute
B
The presence of arterial anastomoses in the heart A) increases the chance of a myocardial infarction by providing more places for blood clots to lodge. B) reduces the chance of a myocardial infarction by providing alternate sources of blood flow to the myocardium. C) increases the time it takes for blood to flow through the coronary circulation. D) is a sign of cardiovascular disease.
B
The repair process that occurs in cardiac muscle following injury consists of the replacement of dead myocardial cells by A) mitosis of existing cardiac muscle cells B) scar tissue C) the migration of immature cardiocytes into the damaged area D) the growth of epithelial cells into the damaged tissue
B
The visceral pericardium is also called the A) endocardium. B) epicardium. C) myocardium. D) mediastinum.
B
What is the effect of norepinephrine on the heart? A) It decreases the rate and strength of contraction. B) It increases the rate and strength of contraction. C) It decreases the amount of blood pumped per minute. D) It has no effect on the heart.
B
Which layer of the heart is correctly matched with the tissue of which it is composed? A) endocardium - cardiac muscle tissue B) fibrous pericardium - stratified squamous epithelium C) myocardium - dense irregular connective tissue D) visceral pericardium - a thin layer of epithelium and loose connective tissue
B
Which of the following vessels is a branch of the left coronary artery? A) left posterior ascending artery B) circumflex artery C) posterior interventricular artery D) left subclavian artery
B
Which of the following would be an effect of cutting the vagus nerve? A) reduced heart rate B) increased heart rate C) reduced strength of contraction D) increased secretion of acetylcholine
B
Any factor that causes a change in heart contractility is called A) a chemotrope B) a chronotrope C) an inotrope D) an isotope
C
Blood leaving the left ventricle goes through which of the following valves? A) biscuspid B) tricuspid C) aortic semilunar D) pulmonary semilunar
C
Cardiac output from the left ventricle is A) normally greater than that of the right ventricle B) probably lower than the right ventricle if the person has systemic edema C) probably lower than the right ventricle if the person has pulmonary edema D) probably higher than the right ventricle if the person has pulmonary edema
C
During the isovolumetric phase of the cardiac cycle A) the atria contract and pump blood into the ventricles B) the ventricles contract and pump blood into the blood vessels C) both atria and ventricles are relaxed D) the ventricles contract but ventricular pressure is lower than arterial pressure
C
If lines were drawn on a typical ECG recording showing where atrial and ventricular systole begin and end, then the ventricular systole would be seen as beginning during a ____ and ending during the next ____. A) P wave; QRS complex B) PR segment; T wave C) QRS complex; T wave D) T wave; P wave
C
If the heart rate is 70 beats per minute and stroke volume is 70 ml, then A) ESV is 140 ml B) ESV is 1 ml C) CO = 4900 ml/min D) CO = 140 ml/min
C
In response to an elevation in blood pressure, the cardiac control center would attempt to restore homeostasis primarily through A) sympthetic stimuli to the ventricular myocardium B) sympathetic stimuli to the SA node C) parasympathetic stimuli to the SA node D) parasympathetic stimuli to the ventricular myocardium
C
In which choice must the first event occur before the second event for normal cardiac activity during one cardiac cycle? A) Purkinje cells depolarize; atrial myocardial cells contract B) ventricular cells contract; atrial cells contract C) atrioventricular valves close; semilunar valves open D) AV node depolarizes; SA node depolarizes
C
Increased input from the baroreceptors to the cardiac control center would cause which of the following to occur? A) increased sympathetic stimulation and decreased parasympathetic stimulation B) increased sympathetic stimulation and increased parasympathetic stimulation C) decreased sympathetic stimulation and increased parasympathetic stimulation D) decreased sympathetic stimulation and decreased parasympathetic stimulation
C
The coronary sulcus is a groove on the outside of the heart that marks the division between the A) left and right atria B) left and right ventricles C) atria and ventricles D) aorta and pulmonary trunk
C
The heart is located A) inside the pericardial cavity. B) in the mediastinum, which is located in the pericardial cavity. C) in the mediastinum, which is located in the thoracic cavity. D) in the thoracic cavity, which is located in the mediastinum.
C
The heart valves A) contract to pump blood through the heart. B) separate the left and right sides of the heart. C) prevent blood from flowing backward through the heart. D) cause the heart sound when they open.
C
The heart would NOT appear on this kind of thoracic section. A) midsagittal section B) transverse section at the level of the 4th rib C) transverse section at the level of the 8th rib D) frontal (coronal) section that also includes the pulmonary trunk
C
The higher the _____, the greater the cardiac output. A) extracellular K+ concentration B) blood pressure in the aorta C) venous return D) level of acetylcholine released at the SA node
C
The location of the heart is correctly described as A) lateral to the lungs. B) medial to the sternum. C) superior to the diaphragm. D) posterior to the spinal column.
C
The pericardial cavity is between the A) fibrous pericardium and parietal pericardium B) left atrium and left ventricle C) visceral pericardium and parietal pericardium D) endocardium and myocardium
C
The plateau phase of the cardiac myocardial cell potential A) normally keeps the heart from beating faster than 70 - 80 times per minute B) allows the cell to depolarize spontaneously instead of having to be stimulated by nerve fibers C) prevents tetanus, which would cease pumping action of the heart D) allows the myocardial cells time to rest during the contraction
C
The sinus rhythm of a normal adult heart would be about A) less than 40 beats per minute. B) 40 - 50 beats per minute. C) 70 - 80 beats per minute. D) 10 to 120 beats per minute.
C
What do skeletal muscle cells, cardiac autorhythmic cells, and cardiac contractile cells have in common? A) In all three, depolarization to threshold is caused primarily by K+ outflow B) In all three, depolarization between threshold and peak membrane potential is caused entirely by Na+ inflow C) In all three, repolarization is caused by K+ outflow D) In all three, the depolarization phase is longer than the repolarization phase
C
When the right atrium contracts, it pushes blood into the A) superior and inferior vena cavae. B) left atrium. C) right ventricle. D) aorta.
C
Which of the following heart chambers is correctly associated with the blood vessel that enters or leaves it? A) right atrium - pulmonary veins B) left atrium - aorta C) right ventricle - pulmonary trunk D) left ventricle - superior and inferior vena cavae
C
Which part of the cardiac cycle occurs between the time the AV valves close and the semilunar valves open? A) atrial systole B) atrial diastole C) isovolumetric phase of ventricular systole D) ejection phase of ventricular systole
C
Which statement is correct concening pulmonary circulation? A) Oxygen rich blood returns from the lungs to the heart through the pulmonary arteries. B) Oxygen poor blood leaves the heart and goes to the lungs through the pulmonary veins. C) Oxygen poor blood returns from the body to the heart through the vena cavae. D) Oxygen rich blood leaves the heart and goes to the body through the vena cavae.
C
Which structure is present in the cardiac muscle tissue but not skeletal muscle tissue? A) striations B) nuclei C) intercalated disks D) t-tubules
C
Which two layers are the most similar in tissue structure? A) fibrous pericardium and visceral pericardium B) fibrous pericardium and endocardium C) visceral pericardium and parietal pericardium D) myocardium and endocardium
C
With respect to the effect on cardiac output, the term preload refers to A) the force developed by the myocardial cells during ventricular systole B) the blood pressure in the aorta and pulmonary trunk during ventricular systole C) the amount of tension developed in the myocardium before it contracts D) anything that decreases stroke volume
C
At a heart rate above 180 beats per minute, all of these decrease except A) cardiac output B) filling time C) stroke volume D) end systolic volume
D
Based on the information given below, which individual has the greatest tolerance for strenuous exercise? Assume they are similar in terms of size and muscular fitness. A) Ann, cardiac reserve = 8 L/min B) Betsy, cardiac reserve = 15 L/min C) Carla, cardiac reserve = 18 L/min D) Donna, cardiac reserve = 25 L/min
D
Because of the distribution of the cardiac impulse by the conduction system, ventricular contraction begins A) in the semilunar valves and then pushes blood toward the interventricular septum B) in the papillary muscles and causes the atrioventricular valves to open C) in the superior part of the ventricles and pushes blood toward the apex D) at the apex of the heart and pushes blood toward the semilunar valves
D
Contraction of a ventricular chamber is called A) diastole. B) diastasis. C) hypertrophy. D) systole.
D
Damage to cells of the AV bundle would prevent the cardiac impulse from reaching the A) SA node B) atria C) AV node D) ventricles
D
Damage to which of the following parts of the brain would cause the body to have less control over cardiac activity? A) cerebral cortex B) thalamus C) basal nuclei D) medulla oblongata
D
In normal individuals, about 2/3 of the total mass of the heart is located A) above the aortic arch B) on the right side of the thoracic cavity C) on the left side of the thoracic cavity D) in the right ventricle
D
Inhibition of the SA node by the parasympathetic division of the ANS is called A) cardioacceleration B) inotropia C) bradycardia D) vagal tone
D
Phophodiesterase is the enzyme that degrades cAMP. A drug that inhibits phosphodiesterase would have what effect on the heart? A) It would decrease cardiac contractility by causing increased removal of Ca2+ from the cell. B) It would increase heart rate but have no effect on contractility. C) It would have no effect, because cAMP is not involved in altering cardiac contractility D) It would increase cardiac contractility by prolonging Ca2+ availability inside the cell.
D
Pressure in the ventricles would be highest during A) atrial diastole B) atrial systole C) ventricular diastole D) ventricular systole
D
Stroke volume times heart rate equals A) blood pressure B) afterload C) end systolic volume D) cardiac output
D
The ANS is the main extrinsic control for cardiac activity, acting through both sympathetic and parasympathetic fibers innervating the heart. This control system is not symmetric--one part of the ANS has less control over the heart. Which of the following statements is NOT correct? A) The sympathetic division has significant control of heart rate through its action at the SA node. B) The sympathetic division has significant control of contractility through its action on the ventricular myocardium. C) The parasympathetic division has significant control of heart rate through its action at the SA node. D) The parasympathetic division has significant control of contractility through its action on the ventricular myocardium.
D
The Frank-Starling law of the heart says that the higher the end diastolic volume, the A) lower the cardiac output B) higher the end systolic volume C) lower the blood pressure D) higher the stroke volume
D
The Purkinje fibers are found in which layer of the heart wall? A) endocardium B) epicardium C) fibrous pericardium D) myocardium
D
The alternate contraction and relaxation of the atria and ventricles are referred to as the A) cardiac output B) coronary circulation C) cardiac conduction system D) cardiac cycle
D
The anterior and posterior interventricular sulci mark the position of which internal heart structure? A) bicuspid and tricuspid valves B) semilunar valves C) fossa ovalis D) interventricular septum
D
The apex of the heart A) is part of the left ventricle wall. B) points inferiorly and laterally. C) is at the approximate level of the 5th intercostal space. D) All of the above are correct concerning the apex of the heart.
D
The cardiac pacemaker potential is caused by cyclic changes in membrane potential that occur in which of the following sequences? A) slow inflow of Na+ ; rapid K+ inflow; slow K+ outflow B) slow inflow of Ca2+ ; rapid Na+ inflow; rapid K+ outflow C) slow inflow of K+ without Na+ outflow; rapid Na+ inflow; rapid K+ outflow D) slow inflow of Na+ without K+ outflow; rapid Ca2+ inflow; rapid K+ outflow
D
The semilunar valves close at the beginning of A) atrial systole B) atrial diastole C) ventricular systole D) ventricular diastole
D
What is located in the pericardial cavity? A) the heart B) the fibrous pericardium C) the mediastinum D) a small amount of serous fluid
D
Which chamber of the heart has to work the hardest (pump against the highest pressure)? A) right atrium B) left atrium C) right ventricle D) left ventricle
D
Which choice would not increase cardiac output? A) increase heart rate, increase stroke volume B) increase heart rate, no change in stroke volume C) no change in heart rate, increase stroke volume D) decrease heart rate, no change in stroke volume
D
Which of the following components of an ECG is not correctly matched with the corresponding event occurring in the heart? A) P wave - atrial depolarization B) PR interval - AV node conduction C) QRS complex - ventricular depolarization D) T wave - atrial repolarization
D
Which of the following is not associated with atrioventricular valves? A) chordae tendineae B) cusps C) papillary muscles D) arteries
D
Which of the following parts of the cardiac conduction system is correctly matched with its location? A) AV bundle (bundle of His) - upper part of interatrial septum B) AV node - left atrium in the inferior interventricular septum C) Purkinje fibers - epicardium of the ventricles D) SA node - right atrium near the opening of the superior vena cava
D
Which of the following would not increase stroke volume? A) increased venous return B) increased sympathetic stimulation of the myocardium C) increased end diastolic volume D) increased arterial blood pressure
D
While the atria of the heart are in systole A) the ventricles are also in systole. B) the atrioventricular valves are closed. C) blood is being pumped into the aorta and pulmonary trunk. D) blood is being pumped into the ventricles.
D
