Author Question: Which of the following cardiac cells has the slowest action potential? a. Atrial c. Purkinje ... (Read 57 times)

Jramos095 · **on:** Jul 16, 2018

Which of the following cardiac cells has the slowest action potential?

a. Atrial c. Purkinje fiber
b. Ventricular d. Sinoatrial node

Question 2

Electrical stimulation of a cardiac muscle cell is the definition of which of the following?

a. Contraction c. Polarization
b. Refraction d. Depolarization

daiying98 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: D
The slope of phase 0 of the sinoatrial node (pacemaker) is less than those of the atrial, ventricular, and Purkinje fiber action potentials, and the former often is referred to as a slow action potential, whereas the latter are called fast action potentials.

Answer to Question 2

ANS: D
The action potential begins when the cell membrane of the excitable cell is exposed to a depolar-izing current and eventually reaches its excitation threshold potential. This is known as depolari-zation.