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Quiz on Chapter 14 , created by x x on 27/06/2019.

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Chapter 14

Question 1 of 31

1

What causes the self-excitation (spontaneous generation of action potentials) of the cells of the sinoatrial (SA) node?

Select one of the following:

  • a) the condition of sinus block;

  • b) slow Na+ influx through non-inactivating sodium channels;

  • c) systemic neuronal inputs to the cells of the SA node.

Explanation

Question 2 of 31

1

What type of ion transport is responsible for the fast depolarization phase of the action potential in myocardial muscle cells?

Select one of the following:

  • a) Mg2+ influx;

  • b) Cl- efflux;

  • c) Na+ influx.

Explanation

Question 3 of 31

1

The plateau phase of the myocardial action potential is caused by the following ion transport:

Select one of the following:

  • a) passive Ca2+ transport;

  • b) passive Cl- and active Ca2+ transports;

  • c) active Na+ and passive Ca2+ transports.

Explanation

Question 4 of 31

1

In the electrical network of the heart, do structures other than the sinoatrial (SA) node have a pacemaker properties?

Select one of the following:

  • a) no;

  • b) yes;

  • c) depends on their functional state.

Explanation

Question 5 of 31

1

423. Under what circumstances the atrioventricular (AV) node takes over the role of leading pacemaker of the heart?

Select one of the following:

  • a) when there is a dysfunction of heart’s innervation;

  • b) when there is ectopic foci;

  • c) when there is a sinoatrial arrest.

Explanation

Question 6 of 31

1

Is there a difference in the rate (frequency) of sinoatrial and atrioventricular potentials?

Select one of the following:

  • a) yes, the sinoatrial node generates potentials with a faster rate;

  • b) no difference;

  • c) yes, the atrioventricular node generates potentials with a faster rate.

Explanation

Question 7 of 31

1

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?

Select one of the following:

  • a) no difference;

  • b) yes, every point of the electrical network of the heart generates a potential with specific form and amplitude;

  • 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.

Explanation

Question 8 of 31

1

Which of the following bioelectrical process take place during the diastolic phase of the heart?

Select one of the following:

  • a) recovery of the ionic concentrations of intra- and extracellular fluids myocardial cells;

  • flow of ionic currents between the Golgi apparatus and the endoplasmic reticulum;

  • generation of reverse action potentials, propagating from myocardial cells to the sinoatrial node.

Explanation

Question 9 of 31

1

The autonomous excitation of the heart is contributed to:

Select one of the following:

  • a) the regular variation of the threshold potential of ventricular myocytes;

  • b) the effect of mechanical pulse waves on the cardiac myocytes;

  • c) special type of ion channels found in the membranes of pacemaker cells.

Explanation

Question 10 of 31

1

Which of the following ions are responsible for the final repolarization phase of the myocardial cells?

Select one of the following:

  • a) K+ efflux;

  • b) Cl- influx;

  • c) Ca2+ influx.

Explanation

Question 11 of 31

1

What is the function of the artificial cardiac pacemaker?

Select one of the following:

  • a) to send electrical pulses to the heart;

  • b) to control the resting potential of pacemaker cells;

  • c) to take over the pumping function of the heart.

Explanation

Question 12 of 31

1

At the end of the “plateau” phase of the action potential in cardiac myocytes, the membrane permeability changes for this type of ions:

Select one of the following:

  • a) sodium ions;

  • b) potassium ions;

  • c) calcium ions.

Explanation

Question 13 of 31

1

The fast depolarisation phase of the action potential of cardiac pacemaker cells is due to:

Select one of the following:

  • a) sodium influx;

  • b) calcium influx;

  • c) potassium efflux.

Explanation

Question 14 of 31

1

The plateau phase of the action potential of cardiac myocytes is due to:

Select one of the following:

  • a) Ca2+ influx through slow voltage-gated channels;

  • b) K+ efflux;

  • c) N+ influx.

Explanation

Question 15 of 31

1

Which cardiac cells exhibit the spontaneous diastolic depolarization?

Select one of the following:

  • a) myocytes of the right atrium;

  • b) myocytes of the left ventricle;

  • c) pacemaker cells.

Explanation

Question 16 of 31

1

The approximate value of the resting potential of cardiac muscle cells is:

Select one of the following:

  • a) -90 mV

  • b) -90V

  • c) -40 mV

Explanation

Question 17 of 31

1

The so called “plateau” phase is found in the action potential of this type of cells:

.

Select one of the following:

  • a) pacemaker cells;

  • b) cardiac muscle cells;

  • c) sinoatrial node

Explanation

Question 18 of 31

1

The action of the anti-arrhythmic pharmaceutical “verapamil” is related to:

Select one of the following:

  • a) blockage of Na+ influx;

  • b) blockage of Ca2+ influx;

  • c) blockage of Mg2+ influx.

Explanation

Question 19 of 31

1

. Which of the following phases is characteristic for the action potential of pacemaker cells of the sinoatrial node?

Select one of the following:

  • a) spontaneous diastolic depolarization;

  • b) stable resting phase;

  • c) the “plateau” phase.

Explanation

Question 20 of 31

1

Which of the following phases is not fond in the action potential of cardiac mysocytes?

Select one of the following:

  • a) spontaneous diastolic depolarization;

  • b) resting phase;

  • c) fast depolarization.

Explanation

Question 21 of 31

1

Which of the following phases is not found in the action potential of pacemaker cells of the sinoatrial node?

Select one of the following:

  • a) spontaneous diastolic depolarization;

  • b) stable resting phase;

  • c) fast depolarization.

Explanation

Question 22 of 31

1

What type of cells are cardiac myocytes?

Select one of the following:

  • a) pacemaker cells;

  • b) contractile cells;

  • c) they have both, contractile and pacemaker functions.

Explanation

Question 23 of 31

1

Self-excitation is a property of:

Select one of the following:

  • a) the electrical conduction system of the heart;

  • b) all cardiac cells;

  • c) the cardiac myocytes.

Explanation

Question 24 of 31

1

What type of cells make up the electrical conduction system of the heart?

Select one of the following:

  • a) pacemaker type;

  • b) phasic type;

  • c) tonic type.

Explanation

Question 25 of 31

1

Myocardial cells are specialised type of striated muscle cells that contract:

Select one of the following:

  • a) voluntarily;

  • b) involuntarily;

  • c) depends on the situation.

Explanation

Question 26 of 31

1

. Choose the correct order of excitation of components of the electrical conducting system of the heart.

......→......→......→......→......→......

Select one of the following:

  • a) bundle of His;

  • b) SA-node;

  • c) Purkinje fibers;

  • d) AV-node;

  • e) atrial myocytes;

  • f) ventricular myocytes.

Explanation

Question 27 of 31

1

Which of the following tissues has pacemaker cells?

Select one of the following:

  • a) myocytes of the ventricles;

  • b) myocytes of the atria;

  • c) the atrioventricular node.

Explanation

Question 28 of 31

1

Choose the correct order of occurrence of the ion currents that comprise action potentials of the cardiomyocytes:

idk answer

Select one of the following:

  • a) K+ efflux;

  • b) Ca2+ influx, K+ efflux;

  • c) K+ efflux, Cl- influx;

  • d) Na+ influx.

Explanation

Question 29 of 31

1

The slow depolarization phase of the action potential in first-order pacemaker cells is due to:

Select one of the following:

  • a) Ca2+ influx;

  • b) Na+ influx;

  • c) K+ efflux.

Explanation

Question 30 of 31

1

What is the original source of the bioelectrical pulses leading to the contraction of the heart?

Select one of the following:

  • a) central nervous system;

  • b) sinoatrial node;

  • c) cardiomyocytes.

Explanation

Question 31 of 31

1

The electrical conduction system of the heart is composed of:

.

Select one of the following:

  • a) muscle cells;

  • b) neurons;

  • c) lymphocytes

Explanation

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