Skeletal Muscle Contraction Review

Flashcards covering key terms and concepts related to skeletal muscle contraction.

Sarcolemma

The plasma membrane of a muscle cell.

Sarcoplasm

The cytoplasm of a muscle cell.

Sarcoplasmic Reticulum

A smoother type of endoplasmic reticulum in muscle cells.

T Tubule

Infoldings of the sarcolemma that penetrate through the muscle cell.

Epimysium

Dense irregular connective tissue surrounding the entire muscle.

Perimysium

Fibrous connective tissue surrounding muscle fascicles.

Endomysium

Fine areolar connective tissue surrounding each muscle fiber.

Fascicle

A group of muscle fibers.

A Band

Dark bands in a myofibril.

I Band

Light bands in a myofibril.

H Zone

The midsection of the A band that is light.

M Line

The midsection of the H zone that is dark.

Z Disc

The midline of the I band.

Actin Filament

Thin filaments composed of two intertwined actin strands.

Tropomyosin

Strands that cover active sites on actin filaments.

Troponin

A protein that changes shape to expose active sites on actin.

Myosin Filament

Thick filaments composed of two heads, one tail, and a flexible hinge.

Sodium Ion (Na+)

Ion that enters the muscle fiber.

Potassium Ion (K+)

Ion that exits the muscle fiber.

Calcium Ion (Ca2+)

Ion responsible for skeletal muscle contraction.

Acetylcholine (ACh)

Neurotransmitter involved in skeletal muscle contraction.