Intrafusal muscle fibers
A)Are found in muscle spindles
B)Are innervated by alpha motor neurons
C)Generate most of the tension in a skeletal muscle
D)Fire continuously at a constant rate
E)Both are found in muscle spindles and generate most of the tension in a skeletal muscle are correct

Question

Quizplus · Accepted Answer

Intrafusal muscle fibers are specialized muscle fibers found within muscle spindles.

Answer: B
 Intrafusal muscle fibers are innervated by gamma motor neurons, not alpha motor neurons.

Answer: E
 Intrafusal muscle fibers are found in muscle spindles and are responsible for sensing changes in muscle length and tension. However, they do not generate most of the tension in a skeletal muscle. The majority of tension is generated by the extrafusal muscle fibers, which are innervated by alpha motor neurons. Intrafusal muscle fibers also do not fire continuously at a constant rate, but rather their firing rate is modulated by gamma motor neurons.

Intrafusal Muscle Fibers