Question

multiple choice question

what are the swellings along the length of a nerve fiber that innervates smooth muscle called?

smooth motor end plates
dense bodies
varicosities

Explanation:

Identify the anatomical structure

Using the Smooth Muscle Characteristics knowledge point

• Smooth muscle lacks highly structured neuromuscular junctions like the motor end plates found in skeletal muscle.
• Instead, autonomic nerve fibers innervating smooth muscle have periodic bulbous swellings along their length.
• These swellings contain synaptic vesicles filled with neurotransmitters and are called varicosities.

Evaluate the incorrect options

• Smooth motor end plates: Motor end plates are specialized regions of the sarcolemma found exclusively at skeletal muscle neuromuscular junctions, not smooth muscle.
• Dense bodies: Dense bodies are intracellular protein structures within smooth muscle cells that anchor thin filaments (analogous to Z-discs in striated muscle), rather than structures on nerve fibers.

Answer:

• Smooth motor end plates
• Dense bodies
• Varicosities (Correct answer)