Muscle systems

A bands

The dark bands in the striations of skeletal muscle; corresponds to the length of the thick (myosin) filaments.

aponeuroses

Broad, flat sheets of dense connective Tissue that connect muscles to other muscles or bone

cardiac muscle

striated, involuntary muscle tissue found only in the heart

cisternae

Enlarged, specialized regions of the sarcoplasmic reticulum that store calcium ions: also called terminal cisternae

Endomysium

the delicate connective tissue sheath surrounding each individual skeletal muscle fiber

Epimysium

The outermost layer of dense connective tissue that surrounds the entire skeletal muscle

Fascia

A sheet of fibrous connective tissue that seperates muscles and muscle groups from each other

Fascicles

Bundles of skeletal muscle fibers (cells) wrapped by the perimysium

H zone

light area in the center of the A band that contains only thick (myosin) filaments (no thin filament overlap_

I bands

The light bands in the striations of skeletal muscle: contains only thin (acting) Filaments

M line

A protiens line in the center of the H zone that holds the thick (myosin) filaments together

Muscle tissue

Specialized tissue respondible for producing movement: includes skeletal, cardicac, and smooth types

Myofibril

A rod like contactile organelle found within the muscle fiber composed of many sarcomeres

Perimysium

The connective tissue layer that surrounds a fascicle (a bundle of muscle fibers)

Sarcolemma

The plasma membrane of a muscle fiber (muscle cell)

Sarcomer

The smallest fundemental contractile unit of a myofibril extending from one Z line to the next

Sarcoplasm

The cytoplasm of a muscle fiber

Sarcoplasmic reticulum

The specialized smooth endoplasmic reticulum in muscle fibers that stores and releases calcium ions

Skeletal muscle

striated, voluntary muscle typically attached to bones responsible for body movement

Skeletal muscle fibers

The long cylindrical, multiinucleated cells for skeletal muscle

Sliding filament theory

mechanism of muscle contraction where actin (thin) filaments slide past myosin (thick) filaments shortening the sarcomeres

Smooth muscle

Nonstriated , involuntary muscle found in the walls of hollow organs (viscera)

Strations

The alternating dark (A bands) and light (I bands) bands visible in skeletal and cardiac muscles, reflecting the organized arrangement of myofilaments

Transverse Tubules (T Tubules)

Invaginations of the sarcolemma that carry the electrical impulse deep into the musclee fiber to trigger CA2 release

Z line

A dense line that defines the boundary of a single sarcomere (the anchorage point for the thin filaments)