Select the Correct Statement About the Function of Myocardial Cells

question 71

Multiple Choice

Select the correct statement about the function of myocardial cells.

• A) The refractory period in skeletal muscle is much longer than that in cardiac muscle.
• B) Cardiac muscle cells are innervated by sympathetic, parasympathetic, and somatic nerve fibers so that the nervous system can increase heart rate.
• C) The entire heart contracts as a unit or it does not contract at all.
• D) The influx of potassium ions from extracellular sources is the initiating event in cardiac muscle contraction.

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Definitions:

Stimulant

A substance that raises levels of physiological or nervous activity in the body, typically used to increase alertness, energy, or physical performance.

Tranquilizer

A drug used to reduce tension or anxiety, often by depressing nerve function.

Morphine

A potent opiate analgesic drug used to relieve severe pain, derived from the opium poppy.

Pain Killer

Medication or drugs used to relieve pain, also known as analgesics.