muscles and tissues

Skeletal muscle fibers contain two sets of intracellular tubules that help regulate muscle contraction:

(1) the sarcoplasmic reticulum and (2) the T tubules

direct muscles attachments

- The epimysium of the muscle is fused to the periosteum of a bone or perichondrium of a cartilage

transvere tubes

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Epimysium.

An "overcoat" of dense irregular connective tissue surrounds the whole muscle. This coat is the epimysium, a name that means "outside the muscle."

Endomysium.

Each individual muscle fiber is surrounded by a fine sheath of connective tissue consisting of areolar and reticular fibers. This is the endomysium ("within the muscle").

Sacroplasmic reticulum function

Functions in the regulation of intracellular calcium levels. It stores Ca and releases it when muscle fiber is stimulated to contract

sacroplasmic reticulum

SR is an elaborate, smooth endoplasmic reticulum that mostly runs longitudinally and surrounds each myofibril.

Direct or fleshy attachments -

The epimysium of the muscle is fused to the periosteum of a bone or perichondrium of a cartilage

Indirectly

The muscle's connective tissue wrappings extend beyond the muscle as a tendon or aponeurosis

Troponin:

The other major protein in the thin filament, is a three-polypeptide complex. One of these polypeptides is an inhibitory subunit that binds to actin; another binds to tropomyosin and helps position it on actin. The third binds calcium ions. Both troponin and tropomyosin help control the myosin-actin interactions involved in contraction.

Perimysium and fascicles.

Within each skeletal muscle, the endomysium-wrapped muscle fibers are grouped into fascicles ("bundles") that resemble bundles of sticks. Surrounding each fascicle is a layer of fibrous connective tissue called perimysium ["around the muscle (fascicles)"].

myosin

a fibrous protein that forms (together with actin) the contractile filaments of muscle cells and is also involved in motion in other types of cells

Tropomyosin:

a rod-shaped protein, spiral about the actin core and help stiffen it. Successive tropomyosin molecules are arranged end-to-end along the actin filaments, and in a relaxed muscle fiber, they block myosin binding sites on actin so that the myosin heads cannot bind to the thin filaments.

The tendon or aponeurosis

anchors the muscle to the connective tissue covering of a bone or cartilage

Myofilamaent

are the filaments of myofibrils constructed from proteins. The principal types of muscle are striated muscle, obliquely striated muscle and smooth muscle

Sarcoplasm

has numerous glycosomes and a unique oxygen-binding protein called myoglobin, which is similar to hemoglobin

Contractility

is the ability to shorten forcibly when adequately stimulated. This property sets muscle apart from all other tissue types

Myofibrils

most of the muscle volume.....fiber that perfectly aligned repeating series of dark A bands and light I bands is evident....... Myofibrils are densely packed, rodlike contractile elements

Sacromeres

smallest contractile unit of the muscle..region of a myofibril between two successive Z disc....composed of myofibrils made up of contractile proteins

indirect muscles attachments

the epimysium of the muscle is fused to the periosteum of a bone or perichondrium of a cartilage....very durable due to small size

Myosin tail

two interwoven, heavy polypeptide chains

Myosin head

two smaller, light polypeptide chains called cross bridges that link the thick and thin filaments together