Function and Morphology of Skeletal muscles

Fiber

a long, cylindrical, multinucleated cell, Structural unit

Myofibril

contractile element, create band pattern

Sarcomere

functional unit of the contractile system of muscle

THIN FILAMENT

Actin (G&F)

Regulatory proteins:
▪ Tropomyosin
▪ Troponin

THICK FILAMENT

Myosin

Myoglobin

Act as an oxygen store, and contains Fe like hemoglobin

Collagen

Major component of endomysium

Nebulin

Holds the actin double filament together to form F actin.

Titin

Assists M protein to anchor the meromyosin in the middle of the sarcomere. Contributes to recoil of muscle relaxation.

THE MOTOR UNIT

These fibers contract simultaneously Force production increase; fineness of movement decrease with the number of cells in the unit

isometric contraction

static contraction

concentric contraction

shortening contraction

eccentric contraction

lengthening contraction