Chapter 09: Assessment of Cardiovascular Function

Chapter 09: Assessment of Cardiovascular Function

 

Complete Chapter Questions With Answers

 

Sample Questions Are Posted Below

 

MULTIPLE CHOICE

 

1. The ability of certain specialized cells of the heart to depolarize spontaneously is known as which of the following?

a.	Diastasis	c.	Automaticity
b.	Excitability	d.	Conductivity

 

 

ANS:  C

Automaticity describes the ability of certain specialized cells of the heart to depolarize. Diastasis refers to the long period of reduced ventricular filling that follows the rapid-filling period. Excitability is defined as the ability of a cell to respond to an electrical stimulus. Conductivity is defined as the ability of cardiac tissue to propagate an action potential.

 

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2. Which of the following is defined as “the ability of a cell to respond to an electrical stimulus”?

a.	Conductivity	c.	Excitability
b.	Rhythmicity	d.	Automaticity

 

 

ANS:  C

Excitability is defined as the ability of a cell to respond to an electrical stimulus. Conductivity refers to the ability of cardiac tissue to propagate an action potential. Automaticity describes the ability of certain specialized cells of the heart to depolarize. Rhythmicity refers to the heart’s pacemaker action potential.

 

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3. The ability of cardiac tissue to propagate an action potential is the definition of:

a.	excitability.	c.	conductivity.
b.	automaticity.	d.	depolarization.

 

 

ANS:  C

Conductivity is defined as the ability of cardiac tissue to propagate an action potential. Excitability refers to the ability of a cell to respond to an electrical stimulus. Automaticity describes the ability of certain specialized cells of the heart to depolarize. Polarization occurs when a cell becomes electrically activated.

 

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4. When a cell membrane of an excitable cell is exposed to a depolarizing current, which of the following occurs?

a.	Increased influx of calcium into the cell
b.	Rapid influx of sodium ions into the cell
c.	Increased efflux of potassium out of the cell
d.	Rapid efflux of protein molecules out of the cell

 

 

ANS:  B

An action potential begins when the cell membrane of the excitable cell is exposed to a depolarizing current and eventually reaches its excitation threshold potential. The initial phase of this type of action potential consists of a rapid upstroke or depolarization. This change in membrane potential to a more positive value occurs because of a rapid influx of sodium ions into the cell.

 

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5. A muscle cell cannot be depolarized again during which phases of an action potential?

a.	End of 0 to the beginning of 2	c.	End of 1 to the beginning of 4
b.	Beginning of 1 to the end of 3	d.	Beginning of 0 to the middle of 3

 

 

ANS:  D

The period from the beginning of phase 0 to the middle of phase 3 is referred to as the absolute refractory period or effective refractory period, because regardless of the strength of the stimulus, the myocyte cannot be depolarized again.

 

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