Chapter 17 (The Heart)
The aortic valve opens at _____
The aortic valve opens when the pressure in the ventricle rises above aortic pressure.
The right side of the heart pumps deoxygenated blood into _____.
The right side of the heart pumps deoxygenated blood into the pulmonary arteries, identified as B in the figure.
The main negative chronotropic effect on the heart is exerted by _____.
The vagus nerve's effect on the SA node slows down heart rate.
A person notices his or her heart beat because he or she senses blood being pumped by the heart. Excessive caffeine intake can lead to irregular heart rhythms (arrhythmias) that patients perceive as "skipped beats." Given that caffeine is a stimulant, which of the following mechanisms best explains the reason for the feeling that the heart skipped a beat? a.Purkinje fibers initiate spontaneous action potentials, which cause the ventricles to contract early. b.Action potentials propagate into the ventricles before the contractile cells have repolarized from the previous heartbeat. c.Action potentials are not delayed sufficiently at the AV node. d.Spontaneous action potentials in the SA node overlap such that the repolarizing phase of one action potential cancels out the depolarizing phase of the next.
a
Archie has a resting heart rate of 125 beats per minute. Classify his cardiac dysrhythmia. a.tachycardia b.asystole c.bradycardia d.heart block
a
Carbohydrate groups on the surfaces of erythrocytes determine blood type and are known as: a.antigens. b.antibodies. c.tissue factors. d.agglutinins.
a
Determine the impact if the connection between the sinoatrial (SA) node and the atrioventricular (AV) node becomes blocked. a.The ventricles will contract more slowly. b.The atria will contract more forcefully. c.The ventricles will contract more quickly. d.The ventricular rhythm will not change.
a
The anatomy of the intrinsic conduction system causes contraction of the ventricles to begin at the apex and move superiorly. Why is this important? a.so blood is forced upward, toward the semilunar valves b.because the Purkinje fibers conduct action potentials away from the heart apex c.so the atria can finish contracting before the ventricles contract d.because the AV bundle is the only electrical connection between the atria and the ventricles
a
The cells that rhythmically and spontaneously generate action potentials in the heart are called __________. a.pacemaker b.cells contractile c.cells atrial cells d.ventricular cells
a
The left side of the heart receives blood returning from the: a.pulmonary circuit b.lymphatic circulation c.systemic circuit d.coronary circulation
a
The left ventricle is the chamber with the thickest wall, because: a.it has to generate enough pressure to pump blood throughout the entire systemic circuit b.it pumps the heavier oxygenated blood c.it has to generate enough pressure to pump blood throughout the entire pulmonary circuit d.it receives more blood than the other chambers of the heart
a
What does the ECG wave tracing represent? a.electrical activity in the heart b.contraction of the heart
a
What does the QRS complex represent in the ECG wave tracing? a.ventricular depolarization b. atrial depolarization c. ventricular repolarization d.atrial repolarization
a
Which heart chamber receives blood from the pulmonary veins? a.left atrium b.left ventricle c.right atrium d.right ventricle
a
Which of the following blood types is considered the universal recipient? a.AB+ b.AB- c.O- d.O+
a
Which part of the intrinsic conduction system normally initiates the depolarizing impulse that causes a heartbeat? a.SA node b.Internodal pathway c.AV bundle d.AV node
a
A contractile cell with a sustained membrane potential of 0 mV is experiencing the: a.plateau phase. b.repolarization phase. c.initial repolarization phase. d.rapid depolarization phase.
a.
Rheumatic fever is a complication of untreated strep throat and the biggest cause of valve disorders. It can cause a condition caused aortic regurgitation in which the aortic semilunar valve is damaged and blood flows backwards into the: a.left ventricle b.right ventricle c.pulmonary trunk d.left atrium
a.
Which of the following would increase heart rate? a.epinephrine and norepinephrine b.decreased activity of the sympathetic nervous system c.increased activity of the parasympathetic nervous system d.acetylcholine
a.
How would a decrease in blood volume affect both stroke volume and cardiac output? a.decreased stroke volume and cardiac output b.no change in cardiac output no change in stroke volume and decreased cardiac output c.increased stroke volume and increased cardiac output d.decreased stroke volume and decreased cardiac output
a.decreased stroke volume and cardiac output a decreased blood volume would decrease the end diastolic volume, thus lowering the stroke volume. Although this would initially lead to a decrease in the cardiac output, heart rate would increase because of increased activity of the sympathetic nervous system in an effort to maintain cardiac output.
What does the ECG wave tracing represent? a.electrical activity in the heart b.contraction of the heart
a.electrical activity in the heart the ECG waves show the depolarization and repolarization in various areas of the heart.
When threshold is reached at the SA node (an autorhythmic cell), what channels open causing further depolarization of the membrane? a.fast calcium b.potassium c.fast sodium d.slow calcium
a.fast calcium unlike nerve cells or cardiac muscle cells, fast calcium channels are responsible for the depolarization phase of the autorhythmic cell action potential. When the fast calcium channels open, calcium rushes into the cell making it less negative (or more positive).
What causes the aortic semilunar valve to close? a.greater pressure in the aorta than in the left ventricle b.higher ventricular pressure than aortic pressure c.equal ventricular and aortic pressures
a.greater pressure in the aorta than in the left ventricle backflow of blood in the aorta (towards the left ventricle) closes the aortic semilunar valve.
By what mechanism would an increase in venous return increase stroke volume? a.increased end diastolic volume b.increased end systolic volume c.increased contractility d.decreased end diastolic volume
a.increased end diastolic volume an increase in venous return increases the end diastolic volume. The fibers are stretched more, resulting in an increase in the force of contraction (preload, or the Frank-Starling Mechanism).
Isovolumetric relaxation and ventricular filling (two phases of the cardiac cycle) take place during __________. a.ventricular diastole b.ventricular systoleboth
a.ventricular diastole occur during ventricular diastole when the ventricles are not actively contracting and ejecting blood.
As their name suggests, calcium ion channel blockers block calcium ion channels in the sarcolemma of pacemaker and contractile cardiac muscle cells and slow calcium ion entry into the cell during an action potential. What effects would these drugs have on the myocardial cells? a.There would be an increase in sodium channel reactivation b.There would be a decrease in contractility c.The conduction velocity would increase d.The action potential would be shorter at the plateau phase of the cardiac muscle cell
b
Certain drugs used to treat dysrhythmias, called local anesthetics, work by blocking voltage gated sodium ion channels and slowing the entry of sodium ions into the cell during an action potential. What effects would you see? a.Increase depolarization of the cell b.Decrease depolarization of the cell c.Decrease repolarization of cell d.Increase in hyperpolarization
b
In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells? a.an unstable resting membrane potential in the contractile cells b.the flow of positive ions from adjacent cells c.the flow of negative ions from adjacent cells
b
Place the following parts of the cardiac conduction system in the order in which they transmit the action potential. 1. atrioventricular (AV) bundle 2. Purkinje fibers 3. sinoatrial (SA) node 4. right and left bundle branches a.3, 6, 4, 1, 2, 5 b.3, 6, 1, 4, 2, 5 c.3, 1, 6, 4, 2, 5 d.3, 1, 6, 4, 5, 2
b
The ABO blood group is based on which antigen(s)? a.antigen O b.antigens A and B c.antigen D d.antigen Rh
b
Type A blood contains __________. a.B antigens and anti-A antibodies b.A antigens and anti-B antibodies c.B antigens and anti-B antibodies d.A antigens and anti-A antibodies
b
What blood type is considered the universal donor? a.A+ b.O c.AB+ d.AB
b
What do pacemaker cell action potentials lack? A a.depolarization b.plateau phase c.repolarization d.threshold
b
Which of the following can be used to measure heart rate? a.P-R interval b.R-R interval c.Q-T interval d.S-T segment
b
Which of these people will produce anti-Rh antibodies? a.every Rh+ person, even if they have not been previously exposed to Rh antigen b.an Rh- person who has been previously exposed to Rh antigen and sensitized c.an Rh+ person who has been previously exposed to Rh antigen and sensitized d.every Rh- person, even if they have not been previously exposed to Rh antigen
b
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart? a.AV node b.SA node c.AV bundle (bundle of His) d.Purkinje fibers
b
Which wave on the electrocardiogram (ECG) represents ventricular depolarization? a.P wave b.QRS wave c.R-R interval d.T wave
b
How do cardiac cells sustain a membrane potential of around 0 mV during the plateau phase? a.increased membrane permeability to potassium ions b.calcium channels remain open c.increased membrane permeability to sodium ions d.decrease in the amount of calcium diffusing across the membrane
b.
The rapid influx of calcium ions into pacemaker cells creates a positive membrane potential inside the cell and is responsible for the: a.repolarization phase. b.full depolarization phase. c.slow initial repolarization phase. d.minimum potential phase.
b.full depolarization phase.
Action potentials generated by the autorhythmic cells spread to the contractile cells through what structures in the membrane? a.tight junctions b.gap junctions c.intercalated discs d.desmosomes
b.gap junctions action potentials generated by the autorhythmic cells spread waves of depolarization to contractile cells through gap junctions. If the depolarization causes the contractile cells to reach threshold, they will in turn generate an action potential.
How would an increase in the sympathetic nervous system increase stroke volume? a.increased end diastolic volume b.increased contractility c.decreased end diastolic volume d.increased end systolic volume
b.increased contractility an increase in sympathetic nervous system activity would increase contractility (by increasing available calcium), thus increasing stroke volume. Contractility causes an increase in stroke volume by decreasing end systolic volume; it does not change end diastolic volume.
What ion movement changes the membrane potential in a contractile cell from negative to positive during the rapid depolarization phase? a.outflow of calcium ions b.influx of sodium ions c.outflow of potassium ions d.influx of calcium ions
b.influx of sodium ions
One of the changes that occurs in the pacemaker potential (unstable resting membrane potential) in the SA node (an autorhythmic cell) is a decreased efflux of what ion? a.calcium b.potassium c.sodium
b.potassium if there is a decreased efflux of potassium while there is a normal influx of sodium, the inside of the cell would become less negative. Thus, threshold would be reached. The ability of these autorhythmic cells to spontaneously depolarize is what results in the pacemaker potential.
What does the QRS complex represent in the ECG wave tracing? a.atrial depolarization b.ventricular depolarization c.ventricular repolarization d.atrial repolarization
b.ventricular depolarization the QRS complex represents depolarization in the ventricles, which have greater mass than the atria.
A damaged atrioventricular (AV) bundle or atrioventricular (AV) node will primarily affect the length of the: a.Q-T interval. b.T wave. c.P-R interval. d.P wave.
c
Mr. Ramirez, whose blood type is AB-, has been injured and requires a blood transfusion. Which blood type may be acceptable for Mr. Ramirez to acquire? a.All of the answers are correct b.A+ c.B- d.O+
c
What characteristic differentiates cardiac muscle cells from skeletal muscle cells? ANSWER: a.excitability b.sarcoplasmic reticulum c.intercalated discs d.striations
c
What is NOT part of the cardiac conduction system? a.atrioventricular (AV) node b.sinoatrial sinoatrial (SA) node c.atrioventricular (AV) valve d.atrioventricular (AV) bundle
c
What normally serves as the pacemaker of the entire heart? a.atrioventricular (AV) node b.Purkinje fiber system c.sinoatrial (SA) node d.atrioventricular (AV) bundle
c
Which blood type carries anti-A antibodies in the plasma? a.AB+ b.A+ c.B d.A
c
Which of the following blood types is considered the universal donor? a.AB+ b.AB- c.O- d.O+
c
Which of these structures conduct(s) action potentials the slowest? a.Purkinje fibers b.Bundle branches c.AV node d.AV bundle
c
As a result of the long refractory period in the contractile cell, cardiac muscle can NOT exhibit: a.oxygen debt. b.treppe. c.tetany. d.fatigue.
c.
Increased pressure in the ventricles would close what valve(s)? a.both semilunar and AV valves b.semilunar valves only c.AV valves only
c.AV valves only increased pressure in the ventricles would close the AV valves.
Which happens first, atrial or ventricular depolarization? a.QRS complex b.T wave c.P wave
c.P wave P wave represents atrial depolarization, which leads to atrial contraction
Describe the pressures in the atria and ventricles that would cause the opening of the AV valves. a.Pressures in the atria and ventricles would be equal. b.Pressure in the ventricles would be greater than in the atria. c.Pressure in the atria would be greater than the pressure in the ventricles.
c.Pressure in the atria would be greater than the pressure in the ventricles. higher pressure in the atria than in the ventricles forces the AV valves to open and blood moves into the ventricles.
Autorhythmicity in the heart is the responsibility of: a.skeletal muscle cells. b.contractile cells. c.cardiac pacemaker cells. d.smooth muscle cells.
c.cardiac pacemaker cells.
Put the phases of the cardiac cycle in the correct order, starting after ventricular filling. a.ventricular ejection, ventricular relaxation, isovolumetric contraction b.ventricular ejection, isovolumetric contraction, isovolumetric relaxation c.isovolumetric contraction, ventricular ejection, isovolumetric relaxation d.isovolumetric relaxation, ventricular ejection, isovolumetric contraction
c.isovolumetric contraction, ventricular ejection, isovolumetric relaxation the ventricles must contract and eject blood before they relax and fill again
The aortic valve closes when __________. a.pressure in the left ventricle falls below atrial pressure b.pressure in the left ventricle raises above aortic pressure c.pressure in the left ventricle falls below aortic pressure d.pressure in the left ventricle raises above atrial pressure
c.pressure in the left ventricle falls below aortic pressure The aortic valve closes to prevent backflow of blood into the ventricle.
In order to cause cardiac muscle contraction, the contractile cells must also depolarize. What causes the depolarization of the contractile cells? a.the flow of negative ions from adjacent cells b.an unstable resting membrane potential in the contractile cells c.the flow of positive ions from adjacent cells
c.the flow of positive ions from adjacent cells
Repolarization of an autorhythmic cell is due to the opening of which channels? a.voltage-gated sodium channels b.Chemically gated potassium channels c.voltage-gated potassium channels d.chemically gated calcium channels
c.voltage-gated potassium channels opening of voltage-gated potassium channels causes positive potassium ions to move out of the cell. This efflux of potassium causes the cell to become more negative inside thus, repolarizing the cell.
During a transfusion, if incompatible antigens are introduced, antibodies can bind to foreign antigens, causing them to clump together, or: a.activate. b.coagulate. c.granulate. d.agglutinate.
d
Unlike skeletal muscle action potentials, cardiac muscle action potentials __________. a.begin with a rapid depolarization phase b.have a short refractory period c.do not involve repolarization d.involve calcium voltage-gated channels
d
What activity is occurring in the heart during the Q-T interval on an electrocardiogram (ECG)? a.The ventricular cells are repolarizing. b.The atrial cells are undergoing action potentials. c.The AV node delay occurs as the action potential spreads from the SA node to the atria to the ventricles. d.The ventricular cells are undergoing action potentials.
d
Which blood type is compatible with B during a transfusion? a.O+ b.AB c.B+ d.O
d
Which of the following blood types is incompatible for donation to A+? a.A b.O+ d.O d.B
d
Which of the following donors will be suitable for a recipient with type A+ blood? a.A donor with AB+ blood b.A donor with AB- blood c.A donor with B+ blood d.A donor with O- blood
d
Which of the following is NOT a population of pacemaker cells in the heart? a.Purkinje fiber system b.sinoatrial (SA) node c.atrioventricular (AV) node d.papillary muscles
d
Which of the following pacemaker cell populations has the fastest intrinsic rate of depolarization at about 60-70 times or more per minute? a.Purkinje fiber system b.atrioventricular (AV) node c.atrioventricular (AV) bundle d.sinoatrial (SA) node
d
Which part of the electrocardiogram (ECG) would most be affected by abnormally slow depolarization of the ventricles? a.R-T interval b.P wave c.T wave d.QRS wave
d
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles? a.bundle branches b.Purkinje fibers c.AV bundle (bundle of His) d.AV node e.SA node
d
The long length of the cardiac action potential, at 200-300 msec, allows for: a.less calcium ions to enter cells. b.a reduction in strength of the heart's contraction. c.a faster heart rate. d.an opportunity for the heart to fill with blood.
d.
Which part of the intrinsic conduction system delays the impulse briefly before it moves on to the ventricles? a.Purkinje fibers b.AV bundle (bundle of His) c.bundle branches d.AV node e.SA node
d.AV node the AV node slows down the impulse giving the atria time to contract before the ventricles contract.
Which part of the conduction system initiates the depolarizing impulse, which spreads throughout the heart? a.Purkinje fibers b.AV bundle (bundle of His) c.AV node d.SA node
d.SA node the SA Node spontaneously depolarizes, causing the wave of depolarization that spreads through the rest of the conduction system and heart.
Which of the following would increase cardiac output to the greatest extent? a.decreased heart rate and increased stroke volume b.increased heart rate and decreased stroke volume c.decreased heart rate and decreased stroke volume d.increased heart rate and increased stroke volume
d.increased heart rate and increased stroke volume cardiac output = heart rate x stroke volume
During what phase of the action potential will calcium ions enter the contractile cell as potassium ions exit? a.repolarization phase b.rapid depolarization phase c.initial repolarization phase d.plateau phase
d.plateau phase
Agglutination occurs when blood type B+ receives blood type O in a transfusion. true false
false
Desmosomes present between adjacent cardiac muscle cells allow ions to rapidly pass from one cell to another, permitting communication among cardiac muscle cells. true false
false
Which chamber pumps oxygenated blood out the aorta to the systemic circuit? a.right ventricle b.right atrium c.left atrium d.left ventricle
the left ventricle pumps oxygenated blood out the aorta to the entire body (systemic circuit)
Which chamber receives blood from the superior and inferior vena cavae? a.right ventricle b.left ventricle c. right atrium d. left atrium
the right atrium receives unoxygenated blood from the systemic circuit.
Which heart chamber pumps unoxygenated blood out the pulmonary trunk? a.right atrium b.left ventricle c.right ventricle d.left atrium
the right ventricle pumps unoxygenated blood out the pulmonary trunk to the lungs
he universal blood donor is O since this blood type lacks the A, B, and Rh antigens. true false
true
