A Motor Unit Is

Question

A motor unit is
A) a motor neuron and all of the muscle fibers to which it connects.
B) a sensory neuron and two muscle fibers.
C) a motor neuron and a whole muscle.
D) a sensory neuron and several sarcomeres.
E) a motor neuron and several sarcomeres.

Accepted Answer

A motor unit is defined as a motor neuron and all of the muscle fibers it innervates. This allows for coordinated contraction of muscle fibers within a muscle. Option B is incorrect because a motor unit is specifically a motor neuron, not a sensory neuron. Option C is incorrect because a motor unit innervates only a portion of a whole muscle, not the entire muscle. Option D and E are incorrect because a motor unit is not directly connected to sarcomeres, but rather to muscle fibers.