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Multiple Choice
Where do gamma motor neurons innervate a muscle spindle?
A
At the center of extrafusal muscle fibers
B
At the neuromuscular junction of cardiac muscle
C
At the tendon attachment of skeletal muscle
D
At the contractile ends of intrafusal muscle fibers
Verified step by step guidance
1
Understand the anatomy of a muscle spindle: Muscle spindles are sensory receptors located within skeletal muscles that detect changes in muscle length and contribute to proprioception. They consist of specialized muscle fibers called intrafusal fibers, surrounded by a capsule.
Differentiate between intrafusal and extrafusal muscle fibers: Intrafusal fibers are found within the muscle spindle and are responsible for sensing stretch, while extrafusal fibers are the standard muscle fibers responsible for contraction and generating force.
Learn the role of gamma motor neurons: Gamma motor neurons are responsible for innervating the contractile ends of intrafusal muscle fibers. Their activation adjusts the sensitivity of the muscle spindle by maintaining tension in the intrafusal fibers, even when the muscle is not actively stretched.
Identify the location of gamma motor neuron innervation: Gamma motor neurons specifically innervate the contractile ends of intrafusal muscle fibers, not the center of extrafusal fibers, neuromuscular junctions of cardiac muscle, or tendon attachments of skeletal muscle.
Confirm the correct answer: Based on the anatomy and function of gamma motor neurons, they innervate the contractile ends of intrafusal muscle fibers to regulate the sensitivity of the muscle spindle to stretch.