18580996
Questão 1
Questão
What causes the self-excitation (spontaneous generation of action potentials) of the cells of the sinoatrial (SA) node?
Responda
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a) the condition of sinus block;
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b) slow Na+ influx through non-inactivating sodium channels;
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c) systemic neuronal inputs to the cells of the SA node.
Questão 2
Questão
What type of ion transport is responsible for the fast depolarization phase of the action potential in myocardial muscle cells?
Responda
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a) Mg2+ influx;
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b) Cl- efflux;
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c) Na+ influx.
Questão 3
Questão
The plateau phase of the myocardial action potential is caused by the following ion transport:
Responda
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a) passive Ca2+ transport;
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b) passive Cl- and active Ca2+ transports;
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c) active Na+ and passive Ca2+ transports.
Questão 4
Questão
In the electrical network of the heart, do structures other than the sinoatrial (SA) node have a pacemaker properties?
Responda
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a) no;
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b) yes;
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c) depends on their functional state.
Questão 5
Questão
423. Under what circumstances the atrioventricular (AV) node takes over the role of leading pacemaker of the heart?
Responda
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a) when there is a dysfunction of heart’s innervation;
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b) when there is ectopic foci;
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c) when there is a sinoatrial arrest.
Questão 6
Questão
Is there a difference in the rate (frequency) of sinoatrial and atrioventricular potentials?
Responda
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a) yes, the sinoatrial node generates potentials with a faster rate;
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b) no difference;
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c) yes, the atrioventricular node generates potentials with a faster rate.
Questão 7
Questão
Is there a difference between the form and the amplitude of the action potentials generated in different locations of the electrical conductive system of the heart?
Responda
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a) no difference;
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b) yes, every point of the electrical network of the heart generates a potential with specific form and amplitude;
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c) yes, the sinoatrial node has a specific potential which changes after passing through the atrioventricular node and remains constant until the target muscle cells.
Questão 8
Questão
Which of the following bioelectrical process take place during the diastolic phase of the heart?
Responda
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a) recovery of the ionic concentrations of intra- and extracellular fluids myocardial cells;
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flow of ionic currents between the Golgi apparatus and the endoplasmic reticulum;
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generation of reverse action potentials, propagating from myocardial cells to the sinoatrial node.
Questão 9
Questão
The autonomous excitation of the heart is contributed to:
Responda
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a) the regular variation of the threshold potential of ventricular myocytes;
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b) the effect of mechanical pulse waves on the cardiac myocytes;
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c) special type of ion channels found in the membranes of pacemaker cells.
Questão 10
Questão
Which of the following ions are responsible for the final repolarization phase of the myocardial cells?
Responda
-
a) K+ efflux;
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b) Cl- influx;
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c) Ca2+ influx.
Questão 11
Questão
What is the function of the artificial cardiac pacemaker?
Responda
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a) to send electrical pulses to the heart;
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b) to control the resting potential of pacemaker cells;
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c) to take over the pumping function of the heart.
Questão 12
Questão
At the end of the “plateau” phase of the action potential in cardiac myocytes, the membrane permeability changes for this type of ions:
Responda
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a) sodium ions;
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b) potassium ions;
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c) calcium ions.
Questão 13
Questão
The fast depolarisation phase of the action potential of cardiac pacemaker cells is due to:
Responda
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a) sodium influx;
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b) calcium influx;
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c) potassium efflux.
Questão 14
Questão
The plateau phase of the action potential of cardiac myocytes is due to:
Responda
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a) Ca2+ influx through slow voltage-gated channels;
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b) K+ efflux;
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c) N+ influx.
Questão 15
Questão
Which cardiac cells exhibit the spontaneous diastolic depolarization?
Responda
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a) myocytes of the right atrium;
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b) myocytes of the left ventricle;
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c) pacemaker cells.
Questão 16
Questão
The approximate value of the resting potential of cardiac muscle cells is:
Responda
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a) -90 mV
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b) -90V
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c) -40 mV
Questão 17
Questão
The so called “plateau” phase is found in the action potential of this type of cells:
.
Responda
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a) pacemaker cells;
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b) cardiac muscle cells;
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c) sinoatrial node
Questão 18
Questão
The action of the anti-arrhythmic pharmaceutical “verapamil” is related to:
Responda
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a) blockage of Na+ influx;
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b) blockage of Ca2+ influx;
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c) blockage of Mg2+ influx.
Questão 19
Questão
. Which of the following phases is characteristic for the action potential of pacemaker cells of the sinoatrial node?
Responda
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a) spontaneous diastolic depolarization;
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b) stable resting phase;
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c) the “plateau” phase.
Questão 20
Questão
Which of the following phases is not fond in the action potential of cardiac mysocytes?
Responda
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a) spontaneous diastolic depolarization;
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b) resting phase;
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c) fast depolarization.
Questão 21
Questão
Which of the following phases is not found in the action potential of pacemaker cells of the sinoatrial node?
Responda
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a) spontaneous diastolic depolarization;
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b) stable resting phase;
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c) fast depolarization.
Questão 22
Questão
What type of cells are cardiac myocytes?
Responda
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a) pacemaker cells;
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b) contractile cells;
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c) they have both, contractile and pacemaker functions.
Questão 23
Questão
Self-excitation is a property of:
Responda
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a) the electrical conduction system of the heart;
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b) all cardiac cells;
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c) the cardiac myocytes.
Questão 24
Questão
What type of cells make up the electrical conduction system of the heart?
Responda
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a) pacemaker type;
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b) phasic type;
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c) tonic type.
Questão 25
Questão
Myocardial cells are specialised type of striated muscle cells that contract:
Responda
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a) voluntarily;
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b) involuntarily;
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c) depends on the situation.
Questão 26
Questão
. Choose the correct order of excitation of components of the electrical conducting system of the heart.
......→......→......→......→......→......
Responda
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a) bundle of His;
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b) SA-node;
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c) Purkinje fibers;
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d) AV-node;
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e) atrial myocytes;
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f) ventricular myocytes.
Questão 27
Questão
Which of the following tissues has pacemaker cells?
Responda
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a) myocytes of the ventricles;
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b) myocytes of the atria;
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c) the atrioventricular node.
Questão 28
Questão
Choose the correct order of occurrence of the ion currents that comprise action potentials of the cardiomyocytes:
idk answer
Responda
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a) K+ efflux;
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b) Ca2+ influx, K+ efflux;
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c) K+ efflux, Cl- influx;
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d) Na+ influx.
Questão 29
Questão
The slow depolarization phase of the action potential in first-order pacemaker cells is due to:
Responda
-
a) Ca2+ influx;
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b) Na+ influx;
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c) K+ efflux.
Questão 30
Questão
What is the original source of the bioelectrical pulses leading to the contraction of the heart?
Responda
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a) central nervous system;
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b) sinoatrial node;
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c) cardiomyocytes.
Questão 31
Questão
The electrical conduction system of the heart is composed of:
.
Responda
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a) muscle cells;
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b) neurons;
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c) lymphocytes
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