Muscle Physiology and Contraction · USMLE Step 1

According to the sliding filament theory, which of the following occurs during muscle contraction?

  1. Thick myosin filaments shorten
  2. Thin actin filaments shorten
  3. Thin filaments slide past thick ones
  4. Both thick and thin filaments shorten
Show answer and explanation

Correct answer: Thin filaments slide past thick ones

Muscle contraction occurs by actin (thin) filaments sliding past myosin (thick) filaments — the filaments themselves remain same length; the sliding shortens the sarcomere.

Difficulty: Medium Question 2 of 20

Practice all 20 Muscle Physiology and Contraction questions

Keep practicing

More Muscle Physiology and Contraction questions