Kerala PSC - Biology - Human Body (Nervous System)

Kerala PSC - Biology - Human Body (Nervous System)

  • The fundamental unit of the nervous system - Nerve cell or Neuron
  • Nervous system is formed by brain, spinal cord and sensory receptor nerves.
  • Nerves are the pathways through which messages travel.
  • The functional junction between neurons is called synapse.
  • Neuron has the following parts
    • Cell body
    • Axon
    • Dendron
  • The long fiber that arises from the cell body of a neuron - Axon
  • Axons are enveloped by a covering made of lipid known as Myelin sheath
  • Myelin sheath is white in colour.
  • The neurons that carry impulses from receptors to central nervous system are called sensory neurons.
  • The neurons that carry impulses from the central nervous system to effectors are called motor neurons.
  • Based on the property of nerve fibres, the nerves are classified into
    • Sensory nerves Eg. Optic nerve
    • Motor nerves Eg. Hypoglossal nerve
    • Mixed nerves Eg. Vagus, Facial, Spinal nerves etc
  • Cell bodies of neurons form a group enveloped by a membrane called Ganglion.
  • The region where the axonite of one neuron are connected to the dendrites of another neuron - Synapse
  • Three types of Nervous system are
    • Central nervous system
    • Peripheral nervous system
    • Autonomic nervous system
  • Central nervous system is composed of Brain and Spinal Cord.


Kerala PSC - Biology - Human Body (Nervous System) Kerala PSC - Biology - Human Body (Nervous System) Reviewed by Kerala PSC GK on 4:24 AM Rating: 5

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