Minggu, 24 Maret 2013

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2013 Peripheral Nervous System (PNS)


Peripheral nervous system is the nervous system located outside the central nervous system. Based on the origin, the peripheral nervous system is distinguished into cranial nerve (brain nerve) and spinal nerve.

Cranial nerve functions to transmit impulse from and toward the brain. There are 12 pairs of cranial nerves. The first four pairs bind with cerebrum and the last eight pairs bind with the posterior of brain. Cranial nerve serves the head, face, and upper neck.

Spinal Nerve attaches to both side of spinal which has the function to transmit impulse from and toward bone marraw. Spinal nerve comprises of cervical nerve (8 pairs), thoracic (12 pairs), lumbar (5 pairs), scanal (5 pairs), and coccogeal (1 pairs).

The PNS is classified into somatic and autonomic nervous systems.

Somatic Nervous System
Somatic nervous System serves the skin, skeleton, and tendon. The acts of somatic system are voluntary motion and reflex motion. Voluntary motion always comes from cerebral cortex, while reflex motion is the automatic response the stimulation which occurs very fast.

The shortest distance passed through by nerve impulse while doing reflex motion is called reflex curve. 

Automatic Nervous System
Automatic nervous system is the nerve system which seves the organ, smooth muscle, and some glands that act autonomically (involuntary motion). The system consist of sympathetic and parasympathetic nervous systems. In the both systems, the ganglion connects the central nervous system with body structure served by autonomic nervous system.

Sympathetic Nervous system
Sympathetic nervous system consists of two nerve cord which line the both side bone of marrow, and each of them has ganglion. The largest sympathetic ganglion is located below the diaphragm, and it is called solar plexus. The other ganglion are located near the heart, below the abdomen, and on the neck. The function of sympathetic nervous system is to control the activity of gland and organ Look At table

Parasympathectic nervous system Parasympathetic nervous system is the vague nerve elongating from medulla oblongata, down through neck toward thorax and abdomen. The system has the reverse function os sympathetic nervous system.


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