Lesson 4 (MCQ)

Question 1

The botanical sources of digitalis glycosides are commonly known as:
A) Sunflowers
B) Foxgloves
C) Daisies
D) Roses

Answer 1

Foxgloves

Question 2

Digitalis glycosides are primarily used for the treatment of:

A) Diabetes
B) Hypertension
C) Congestive heart failure
D) Asthma

Answer 2

Congestive heart failure

Question 3

The direct action of digitalis glycosides on the heart results in:

A) Increased heart rate
B) Decreased force of myocardial contraction
C) Positive inotropic effect
D) Vasodilation

Answer 3

Positive inotropic effect

Question 4

How do digitalis glycosides exert their positive inotropic effect?
A) By stimulating adrenergic receptors
B) By inhibiting the sodium pump
C) By blocking calcium channels
D) By activating potassium channels

Answer 4

By inhibiting the sodium pump

Question 5

What is the primary mechanism of action of digitalis glycosides on the sodium pump?
A) They block the binding site of K⁺
B) They increase the transfer of Na⁺ to the outside of the cell
C) They inhibit the transport of K⁺ into the cell
D) They enhance the release of calcium from the sarcoplasmic reticulum

Answer 5

They block the binding site of K⁺

Question 6

Which of the following is NOT an effect of digitalis glycosides on myocardial excitability?
A) Decreased action potential duration
B) Increased refractory period
C) Increased rate of conduction
D) Decreased resting membrane potential

Answer 6

Increased rate of conduction

Question 7

At toxic levels, digitalis glycosides can lead to:
A) Increased conduction velocity
B) Reduced refractory period
C) Ectopic beats
D) Decreased automaticity

Answer 7

Ectopic beats

Question 8

The indirect vagal action of digitalis glycosides is mediated through:
A) Sympathetic nervous system
B) Parasympathetic nervous system
C) Central nervous system
D) Autonomic nervous system

Answer 8

Parasympathetic nervous system

Question 9

How does digitalis glycosides affect the pacemaker activity of the sino-atrial (SA) node?
A) It accelerates the rate of impulse formation
B) It has no effect on the SA node
C) It slows down the rate of impulse formation
D) It stabilizes the resting membrane potential

Answer 9

It slows down the rate of impulse formation

Question 10

Which of the following is NOT a systemic effect of digitalis glycosides?
A) Increased contractility
B) Enhanced response to acetylcholine
C) Sensitization of baroreceptors
D) Decreased heart rate

Answer 10

Decreased heart rate

Question 11

Which of the following glycosides is derived from Digitalis purpuria?
A) Strophantin
B) Digitoxin
C) Digoxin
D) Ouabain

Answer 11

Digitoxin

Question 12

The direct action of digitalis glycosides results in a positive inotropic effect, which refers to:
A) Increased heart rate
B) Decreased contractility
C) Increased force of myocardial contraction
D) Vasodilation

Answer 12

Increased force of myocardial contraction

Question 13

Which of the following is NOT an effect of digitalis glycosides on myocardial excitability?
A) Decreased action potential duration
B) Increased refractory period
C) Decreased rate of conduction
D) Increased resting membrane potential

Answer 13

Increased resting membrane potential

Question 14

What is the direct action of quinidine sulfate on cardiac cells?

A) Increases maximal rate of phase 0
B) Increases slope of phase 4
C) Decreases spontaneous depolarization of Purkinje fibers
D) Prolongs the effective refractory period of normal pacemaker cells

Answer 14

Decreases spontaneous depolarization of Purkinje fibers

Question 15

Which of the following is NOT an adverse effect of quinidine sulfate?
A) Cardiac depression
B) Gastrointestinal upset
C) CNS depression
D) Increased cardiac output

Answer 15

Increased cardiac output

Question 16

How does procainamide differ from quinidine in terms of action?
A) Procainamide has a stronger indirect effect on controlling atrial tachyarrhythmias.
B) Procainamide has less pronounced direct actions.
C) Procainamide is more effective in controlling ventricular arrhythmias.
D) Procainamide is not absorbed rapidly from the GI tract.

Answer 16

Procainamide is more effective in controlling ventricular arrhythmias

Question 17

What is the main action of lidocaine in cardiac cells?
A) Improves conduction in atrial fibers
B) Lengthens action potential duration in Purkinje fibers
C) Shortens action potential duration in Purkinje fibers and myocardium
D) Increases refractory period of ventricular myocardium

Answer 17

Shortens action potential duration in Purkinje fibers and myocardium

Question 18

Which drug is especially good for digitalis-induced ventricular arrhythmias?
A) Quinidine sulfate
B) Procainamide
C) Lidocaine
D) Phenytoin

Answer 18

Phenytoin

Question 19

How does propranolol exert its antiarrhythmic action?
A) By increasing spontaneous firing in the SA node
B) By blocking adrenergic receptors
C) By prolonging action potential duration in ventricular fibers
D) By increasing refractory period in atrial fibers

Answer 19

By blocking adrenergic receptors

Question 20

Which drug is dangerous to use in congestive heart failure?
A) Quinidine sulfate
B) Procainamide
C) Lidocaine
D) Propranolol

Answer 20

Propranolol

Question 21

What is the main pharmacokinetic characteristic of procainamide?
A) Slow absorption from the GI tract
B) Rapid biotransformation in the liver
C) Extensive first-pass effect
D) Prolonged half-life in cats

Answer 21

Slow absorption from the GI tract

Question 22

What effect does atropine-like vagolytic action have in the context of quinidine sulfate use?
A) Increases ventricular rate
B) Decreases atrial fibrillation
C) Prolongs action potential duration
D) Decreases cardiac output

Answer 22

Increases ventricular rate