Skelatol Muscle componets

Sarcolemma

Cell membrane

Sarcoplasm

Cytoplasm

Sarcoplasmic reticulum

Stores Calcium

Transvers Tubules

AKA T-tubules

Conducts impulses from the cell’s surface to the interior of the cell, where actin and myosin meet

Sarcomere

The smallest unit of contraction. Is composed of a combo of thick and thin filaments

I band

Only the thin filament that makes up the lighter portion of striations

A band

Thick filament + overlap with thin filament that makes up the darker part of striations

H zone

A region in the center of an A band that contains only the thick filaments

M line

Region in the center of the H zone that contains proteins that hold thick filaments together at the center of the sarcomere

Z disk

Narrow region that separates sarcomeres

Myomesin

The protein that holds myosin (thick filament) in place

Titin

A protein that forms the core of the thick filament

Tropomyosin

Block myosin attachment sites when at rest

Troponin

Binds to actin, tropomyosin, and calcium ions

String of actin subunits

A polymer formed by chaining together individual globular G-actin monomers

Dystrophin

Links actin in the outermost myofilament to membrane proteins and transfers forces of muscle contraction to tendons (CT)

Muscular Dystrophy

A genetic disease that causes progressive muscle weakness and muscle degeneration due to genetic defects in dystrophin

Triads

T-tubules + SR

Muscle fiber

Long, cylindrical, multineuclenated cells with obvious striations that allow for voluntary movement, locomotion, and facial expressions