Neuron Structure And Functions

          NEURON STRUCTURES AND FUNCTIONS 

 

 Functions of nervous system:- 1. Sensory input, that is, the detection of stimuli by the receptors or sense organ. 2. Transmission of nerve impulse to brain or spinal cord, which generates appropriate response. 3. Motor output, that is, carrying out of response by muscles or glands, which are called effectors. Two types of cells constitute our nervous system. One is neuron and another is neuroglia. Neuron conducts impulses and neuroglia provides support and protection to neuron.  A neuron consists of a cell body called cyton and two processes dendrites and axon. 

 

 Dendrites:- Dendrites are hair like extensions connected to cyton. They receive stimulus, which may be physical, chemical, mechanical or electrical and passes it to cyton. 

 Cyton:- It is the cell body with a central nucleus which is surrounded by cytoplasm. 

 Axon:- From one side of the cyton arises a cylindrical process filled with cytoplasm. It is called axon. It is the largest part of neuron.  It transmitted impulse away from cyton. Its tip has swelling called axon bulb. Generally a neuron has one axon and its terminal may be branched. The ending of axons is called synaptic terminals.  The gap between synaptic terminals and the dendrites of other neuron or effector cells is called synapse. 

 How do we feel a hot or cold object? How do we feel pain?  

=> There are thousands of receptors in our sense organ. They detect stimuli such as heat, cold, pain, smell and tastes. There are different kinds of receptors such as algesireceptors for pain, tangoreceptorsfor touch, gustatoreceptors for taste, olfactoreceptor for smell and so on. The receptors receive stimuli is passed in the form of electrical signals through the dendrites of a neuron to the cyton of the neuron.  The cyton always transmit strong impulses. The weak impulses are not further transmitted. An impulse passed on by the cyton travel along the axon. When it reaches to the end of axon. This causes the axon bulb to release a chemical which diffuses along the synapse and stimulates the dendrites of adjacent neuron. These dendrites in turn send electrical signals to their cell body, to be carried along the axon. Similarly a signal from brain passed on to the effector. In this way we felt heat, cool, smell and taste anything.