The muscular system

The muscular systems function

the function of this system is to move the skeletal system, maintain posture through steady contraction and generate heat through cell metabolism.


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The contractions of the muscles

the contraction of the muscle can be described in 4 stages


1 muscle activation ; the motor nerve stimulates an impulse to pass down a neuron to the neuromuscular junction, this stimulates sarcoplasmic reticulum to release the Ca ion to the muscle cell.

2 muscle contraction; Ca flows in to the muscle cell, makes actin and myosin to bind up. The actin and myosin cross bridge contract using energy as AT

3 recharging; ATP is re-synthesized allowing actin and myosin to hold their strong binding together.

4 the impulse of the nerve stop caused the Ca to flow back to the sarcoplasmic reticulum that unbounded the actin and myosin , from then the muscle relaxed

2 disorders found in the muscular system

muscular dystrophy : this type of disorder is inherited and can spread by the mother. It causes the muscle to lack of the protein called dystrophin that holds the skeletal muscle cells together and the muscle tissues are replaced by the fatty deposits.

the symptoms are the weakening of the muscle, the fatigue of the muscle eventually loss of strength. there is no treatment that can fully cure this type of disorder but some medication can slow down the course of the disease.


ALS ; a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body.

the symptoms are the weakening of the muscles and fatigue. there is no treatment that can fully cure the disease but some medication can slow the symptoms down.

The 3 types of muscle tissue

The 3 types of muscle tissue are cardiac, smooth, and skeletal. Cardiac cells are located in the walls of the heart, appear striated, and are under involuntary control. Smooth muscle fibers are located in walls of hollow visceral organs, except the heart, appear spindle-shaped, and are also under involuntary control. Skeletal muscle fibers occur in muscles which are attached to the skeleton. They are striated in appearance and are under voluntary control.

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the structure of a sarcomere

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