Structure Of Skeletal Muscle

Structure Of Skeletal Muscle

Write a short note on the nerve supply of a skeletal muscle.
Answer. The nerves supplying skeletal muscles are somatic nerves and consist of three functional components.

Nerve Supply Of Motor fibres: They enter the individual muscle fibres at a point called motor end plate/neuromuscular junction. The nerve fibres are of following two types:

• Alpha motor fibres arising from alpha motor neurons of anterior horn cells and supply the extrafusal muscle fibres.
• Gamma motor fibres arising from gamma motor neurons of anterior horn cells and supply the intrafusal muscle fibres of muscle spindle (sensory end organ of skeletal muscle).

Nerve Supply Of Sensory fibres:

• Myelinated fibres: They are distributed to muscle spindles, tendon and fascia of the muscle and carry exteroceptive and proprioceptive sensations. The fibres carrying pain sensations are free nerve endings around the muscle fibres, while the fibres carrying sensation of tension and degree of contraction, end in special sense organs called Golgi tendon organs.
• Nonmyelinated fibres: Distribution of these fibres is not known as yet.

Autonomic fibres: These fibres innervate the smooth muscle of the blood vessels present within the muscle. These fibres thus regulate the amount of blood flow in the muscle.