Question

Which of the following is FALSE when referring to motor units?

A. Motor units are comprised of gamma motor neurons and all of the muscle fibers innervated by it.
B. Slow motor units are resistant to fatigue, but only produce a small amount of force relative to the other muscle types.
C. Fast fatigable motor units have the fastest contraction of the three types, but very poor myoglobin stores.
D. Fast fatigue-resistant motor units can sustain about 60% of their maximum force for about 20 minutes.
E. A fast twitch muscle is going to have a higher muscle fiber to nerve ratio than a slow twitch fiber.

Answer 1

The false statement is A, as motor units are comprised of alpha motor neurons and the muscle fibers they innervate, not gamma motor neurons.

Step-by-step explanation:

Among the statements regarding motor units, the false one is: A. Motor units are comprised of gamma motor neurons and all of the muscle fibers innervated by it. In fact, motor units are made up of alpha motor neurons and the muscle fibers they innervate. Options B, C, D, and E are all true characteristics of different muscle fiber types and their corresponding motor units. It's important to note that motor units play a critical role in how muscle contraction and control are executed, with smaller motor units being activated before larger ones as required force increases—a process known as recruitment.