Question

What is the function and basic structure of the nervous system?

Answer 1

NERVE SYSTEM

          * Nerve system is divided into two

                           * Central nerve system.(CNS)

                                     * It consist of brain and spinal cord.

                           * Peripheral nerve system.(PNS)

                                     * It include all neural structures outside CNS.

                                       (Peripheral nerves,ganglia,autonomic nerve system.)

Basic structure of nerve system.

          * The structural organization of nerve system is divided into two type of cells

                                     * Neurons

                                     * Neuroglia.

               * Neurons.

                         * Neuron consist of a cell body and processes.

                                 * Cell body or soma.

                                          * It consist of a mass of cytoplasm surrounded by plasma

                                            membrane and contain large vesicular nucleus with prominent

                                            nucleolus.

                                          * The main features of cytoplasm of the neurons are

                                                   # Presence of Nissl bodies or nissl substance.

                                                         * It contain rough endoplasmic reticulum with ribonucleic

                                                            acid help in protein synthesis.

   # Presence of Neurofibrils.

                                                         * Neurofibrils are filamentous strands of proteins.

                 * Process.

                       * Processes divided into two types.

                                 * Short processes which are numerous called dendrites.

                                           * Dendrites brings impulses towards the cell body.

                                  * Single large process is called axon.

                                              * it conduct nerve impulse away from the cell body.

                                              * Myelinated axons are called nerve fibers.

                                              * Axons termination to form telodendria which consists

                                                of presynaptis knobs.

             * Neuroglia.

                      * It provide structural and functional support to the axons.

                      * Neuroglia is numerous and account for more than half of the

                        brain's weight.

                      * Structure of neuroglia consist of highly branched cells and occupy the

                        spaces between the neurons to create a microenvironment for neural

                        activity.

                               * Neuroglia in CNS.

                                         * Asterocytes.(Form blood brain barrier)

                                         * Oligodendrocytes.(Form myelin sheath around fibers of CNS)

                                         * Ependymal cells.(Line the ventricles of brain)

                                         * Microglia.( Phagocytic cells)

                             * Neuroglia in PNS.

                                        * Capsular cells.( Provide support ans nutrition)

                                        * Schwann cells.(Form myelin sheath around fibers of PNS.)

                                    

Functions of nerve system.

    * Receiving stimuli from within and outside of the body.

    * Initiation and execution of motor responses.

    * Integration of sensory information.

    * Help to maintain homeostasis in the body.

    * Controlling muscles and glands of the body.

      * Reflex arc (Automatic involuntary refex) ia a function of nerve

                      system help the individual for react to a stimulus.