The musculoskeletal system explained

Skeletal muscles are a type of striated muscles attached to the skeleton, made up of cells or elongated, multinucleated their cores located on the periphery fibers. The musculoskeletal system is vital for movement and other motor functions. The musculoskeletal system plays an important role in coordination of movement, too.

Obey the organization of actin and myosin proteins and confer that striation which is perfectly seen under a microscope. They are used to facilitate movement and maintaining bone-joint union through his contraction.They are generally voluntary contraction (through nervous innervation), although they can contract involuntarily.
The human body comprises about 90% of such 10% muscle and cardiac muscle and visceral.

Muscles have a great capacity for adaptation, changed more than any other organ both its content and its form. In severe atrophy can return to reinforce in a short time, thanks to training, as with the disuse atrophy leading to a decrease in muscle size, strength, even reducing the number of cell organelles.

If it is immobilized in shortening position, after a short time adapts to his new length requiring training base stretches to return to its original length, even if left stretched a time, it can give instability to articulate by adopted hyper-mobility.

The musculoskeletal system explained

The muscle due to its high power consumption, requires a good blood supply to bring you food and eliminate waste, that by the pigment of muscle cells, give the muscle a reddish appearance in the living being.

In the endplate (neuromuscular junction or synapse) the neurotransmitter acetylcholine (ACh) is released, this neurotransmitter acts in the sarcolemmal opening channels that allow indiscriminately step of sodium and potassium.

The electrochemical gradient allows more sodium ions on entering these in large amount, an action potential occurs since the cell membrane is rich in fiber channels voltage-dependent sodium, stimulating muscle fiber.

The action potential originated from the sarcolemma, produces a depolarization of the latter, it said depolarization coming into the cell, particularly the sarcoplasmic reticulum, causing the release of calcium ions previously accumulated in this and the terminal cisternae.

Secretion of calcium ions leads to the actin-myosin complex, which makes these proteins to bind and rotate on itself, causing a shortening, later, the calcium ions can return to the sarcoplasmic reticulum for next contraction.

Microscopic view of skeletal muscle

Skeletal muscle is a tissue composed of spindle cells or muscle fibers, consisting of the following elements.

Sarcolemma, is the cell membrane, runs along the muscle fiber and its end is fused to the tendon, and this in turn is fused to the bone.

Sarcoplasm, muscle cell cytoplasm containing organelles and other elements that follow.

Cell nuclei, which are located in the periphery of the interior, in this case there are several cores to a single muscle cell.


Actin and myosin is a protein complex web of polymer fibers whose main property, call contractility, is to shorten its length when subjected to a chemical or electrical stimulus.

In a muscle cell we find between 1500 myosin and actin 3000. These proteins have a helical or helix, and when activated together and rotate so that produces a shortening of the fiber.

During a single movement several processes exist attachment and detachment of actin-myosin assembly. Each muscle fiber contains hundreds to thousands of myofibrils.


reticulum surrounding muscle fibers results from the invagination of the sarcolemma, this reticulum in turn contains a system of tubules (T muscular System) terminals and tanks containing large amounts of calcium, essential for working muscles.

Keywords: musculoskeletal system, musculoskeletal system in man, musculoskeletal system in women


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