Smooth and Cardiac Muscle Physiology · Physiology

Which factor primarily determines the strength of cardiac muscle contraction?

  1. Fiber length and calcium level
  2. Number of recruited motor units
  3. Frequency of incoming nerve impulses
  4. Degree of temporal summation
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Correct answer: Fiber length and calcium level

Cardiac contractile force depends on fiber length and intracellular calcium levels. This relationship is described by the Frank-Starling mechanism.

Difficulty: Medium Question 16 of 20

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