What are the main functions of skeletal muscle?

Skeletal muscles have three primary functions: movement (contracting to move the body and limbs), posture and support (maintaining posture and stabilizing joints), and heat production (generating heat through metabolic activity to aid thermoregulation).

What are the different types of skeletal muscle fibers?

There are two main types: Type I (red fibers) are slow-twitch, fatigue-resistant, and suited for endurance activities like posture. Type II (white fibers) are fast-twitch, quick to fatigue, and adapted for rapid, forceful movements like eye motion.

How are skeletal muscles innervated?

Each skeletal muscle is innervated by a mixed peripheral nerve containing motor fibers (α-motor neurons) to stimulate contraction, γ-motor fibers for intrafusal fibers, and sensory fibers for proprioception. The nerve enters at a motor point, relevant in physiotherapy.

What is the microscopic structure of a skeletal muscle fiber?

A skeletal muscle fiber is a long, cylindrical, multinucleated cell with cross-striations. It has a sarcolemma (plasma membrane), sarcoplasm (cytoplasm with myofibrils), and sarcomeres (contractile units with A and I bands that slide during contraction).

What are the gross anatomical features of a skeletal muscle?

Key gross features include the origin (fixed proximal attachment), insertion (mobile distal attachment), belly (fleshy contractile part), and tendon (cord-like attachment that transmits force to bones).

How does fascicular architecture affect muscle function?

Fascicular architecture affects strength and range of motion. Patterns include parallel (long fibers), convergent (fan-shaped), pennate (feather-like), spiral/cruciform (twisting), and sphincteric (circular), each suited to different functions.

What clinical conditions are associated with skeletal muscles?

Common clinical conditions include muscle paralysis (from motor neuron damage, with spastic or flaccid types), Myasthenia Gravis (autoimmune weakness), and rigor mortis (postmortem stiffening from ATP depletion).

Skeletal Muscle – Structure, Fiber Types & Function

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