Which of the following does NOT correctly describe cardiac muscle cells?
A)They are arranged in layers surrounding hollow cavities in the heart.
B)They are much shorter than skeletal muscle fibers,and generally have a single nucleus.
C)Their membranes are depolarized initially by the influx of sodium ions.
D)They depolarize prior to contraction.
E)They can contract in the absence of external calcium.

Question

Which of the following does NOT correctly describe cardiac muscle cells?
A)They are arranged in layers surrounding hollow cavities in the heart.
B)They are much shorter than skeletal muscle fibers,and generally have a single nucleus.
C)Their membranes are depolarized initially by the influx of sodium ions.
D)They depolarize prior to contraction.
E)They can contract in the absence of external calcium.

Quizplus · Accepted Answer

Cardiac muscle cells cannot contract in the absence of external calcium. Calcium ions are required for the interaction between the contractile proteins, actin and myosin, to occur, leading to muscle contraction.

Which of the Following Does NOT Correctly Describe Cardiac Muscle Cells