BIOL 1503 Chapter : Physiology Of Muscles
Document Summary
Vertebrate skeletal muscle: a skeletal muscle consists of a bundle of long fibers, each a single cell, running parallel to the length of the muscle. Each muscle fiber is itself a bundle of smaller myofibrils arranged longitudinally. Thin filaments consist of two strands of actin and two strands of a regulatory protein the ones that actually move. Thick filaments are staggered arrays of myosin molecules stationary and pull actin together. The functional unit smallest active part of a muscle is called a sarcomere and is bordered by z lines. The sliding-filament model of muscle contraction: according to the sliding-filament model, filaments slide past each other longitudinally, producing more overlap between thin and thick filaments. The head of a myosin molecule binds to an actin filament, forming a cross-bridge and pulling the thin filament toward the center of the sarcomere: muscle contraction requires repeated cycles of binding and release.
