Which of the following statements regarding skeletal muscle is TRUE?
A)Skeletal muscle fibers have pacemaker activity.
B)Skeletal muscle fibers are joined together by gap junctions.
C)A given skeletal muscle fiber will contract when excitatory nervous stimuli sufficiently exceed inhibitory nervous stimuli at the motor end plate.
D)A given skeletal muscle fiber will contract if excitatory synaptic inputs sufficiently exceed inhibitory synaptic inputs on the motor neuron that innervates that fiber and the motor neuron fires an action potential.
E)Skeletal muscle contraction is inhibited by inhibitory motor neurons that synapse onto skeletal muscle fibers.

Question

Quizplus · Accepted Answer

A given skeletal muscle fiber will contract if excitatory synaptic inputs sufficiently exceed inhibitory synaptic inputs on the motor neuron that innervates that fiber and the motor neuron fires an action potential. This action potential triggers the release of calcium ions from the sarcoplasmic reticulum within the muscle fiber, leading to muscle contraction. Gap junctions and pacemaker activity are not characteristic of skeletal muscle, and inhibitory motor neurons can only inhibit, rather than promote, skeletal muscle contraction.

Which of the Following Statements Regarding Skeletal Muscle Is TRUE