Function:
Functionally, the nervous system resembles the system of electric conduksi: Organize and control all activities of the body. In general, the function of the nervous system is divided into 4 parts:1. Receiving the stimulus / information from internal and external environment through afferent nerve fibers or through sensory channels.
2. Communicating the information received to the central nervous system.
3. Memperoses information received on the brain and spinal cord to menetukkkan specific responses to stimuli.
4. Transmit information to efferent nerve or motor point to the effector organs.
Neuron
Neurons are: The basic structure and functional units of the system persyarafan. These neurons are found in all body cells and provide biological and biochemical effects on the body. Cells - nerve cells varied in size and shape according to their function - respectively. Each - each cell has a nucleus and granules and fibrils in the cytoplasm. Neurons act like a miniature nervous system and nempunyai trait very typical for electrical function.
By microscopic neuron consists of: cell body or soma, axon and dentrit. Soma, axon and dendrites are enveloped by the cell membrane, which separates it from the outside of the cell. The existence of a broad surface on the cell membrane making it more receptive to a large number of synaptic contacts at a time (See picture) Dendrites: short fibers that are attached to the outside of the cell, where the entry of impulses from cell to cell to another. Axon is: Fiber where nerve impulses are transmitted to the outgoing cells to other cells. The amount is usually a single axon.
Cell membrane
Cell membrane is a membrane that limits the content of the cell and its surroundings. Many important functions of neurons located in the cell membrane itself. The structure of the cell membrane composed of proteins and fats in which the material can move - move. Memberan cells have differences in permebialitasnya, where permibialitas of Oxygen, Carbon dioxide and ions - organic ions and not permeable to proteins and inorganic ions. This permebialitas difference is due to the distribution or movement of ions - ions. In the cells contain more potassium and outside the cells contain more sodium. Entry of sodium and potassium out of and into the cell (the active mechanism of sodium potassium pump) causes the difference in membrane permeability of these cells. Crossing ions through the cell membrane caused a difference in electric charge outside the cell (more + +) is called: resting membrane potential. Cells in this state, any time can experience the action potential is called polarization. Polarization: the electrical charge difference between the outer cell membrane and inside (outside of being - and in a +)
Excitability
Excitability is: Postensial rest on neurons in an unstable state. For example: the membrane of nerve to react to stimuli, chemical substances that enter and damage mechanics. This unstable situation will cause the action potential. This action potential occurs with the following mechanism: When the neuron is stimulated, the cell membrane permebialitas against Na + is significantly increased, and will cause a sudden displacement of Na + into the cell membrane. This situation led to a positive charge in the cell (depolarisation). At the time of Na + entry, then K + is also moving out of the cell. Active Transport carrying potassium and sodium moves into its original state is called: repolarization. Action potential occurred within 1-2 msec.
Myelin
Myelin is a wrapping axons. Actually myelin was covered or protected anymore by cells called Schaw cells. Its function as an insulator: Preventing the flow of ions through the axon and the membrane. Throughout the 1 mm of myelin are nodes of Ranfier which is an area that is free.
Synapse
The relationship between one neuron to another neuron called Synapse. Synapse is a point of communication between neurons is one with which lainnya.Transmisi impulses at this happens in chemical synapses. When the impulse came at the synapse, the chemical transmitter release, both excitation and release substances to stimulate the neurons or are inhibitors and release substances to inhibit neurons.
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