Nerve Tissue

• Motor Neurons

  • Has a cell body consisting of cytoplasm and a nucleus.
  • Cytoplasm contains dark Nissl granule, which are rich in RNA and are involved in protein synthesis.
  • Dendrites and Axons extend from the cell body.
  • Dendrites conduct nerve impulses to the cell body
  • Axons conduct nerve impulses away from the cell body.
  • One or more dendrites may be present.
  • Nerve fibres outside of the CNS are enclosed by a myelin sheath.
  • Myelin insulates nerve fibres and accelerates impulse transmission.
• Transmission of Nerve Impulses

  • Neurons are interconnected to form a continuous conduction system.
  • Axon of one neuron connects to the dendrite of the next neuron
  • Neurons are separate by synaptic gaps.
• Synapse

  • Impulses move along the axon to the synaptic knob.
  • Each synaptic knob has many synaptic vesicles with a neurotransmitter.
  • Impulses cause synaptic vesicles to burst, release neurotransmitters in the synaptic gap.
  • Neurotransmitters move across the synaptic gap and generate electrical signals that are conducted as nerve impulses to the next neuron.