nervous tissue

    Cards (16)

    • Function of the nervous system
      Provide rapid and precise communication between different parts of the body via the action of neurones
    • Neuron
      • Specialised for intercellular communication
      • Displays substantial variation in size and shape but all have the same basic structure
    • Dendrites
      • Highly branched processes extending from cell body
      • Form synapses with adjacent neurones
      • Respond to external stimuli
      • Convey incoming information to cell body
    • Cell body
      • Large nucleus and prominent nucleolus
      • Nissl bodies
      • Numerous mitochondria
    • Axon
      • Rapidly propagates signal from cell body towards axon terminals
      • Specialised to conduct action potentials
      • PNS - myelinated or non-myelinated
      • CNS - myelinated
    • Terminal boutons
      • Form synapses with other neurones or effector organs
      • Communication junctions (eg neuromuscular junctions)
      • Here electrical signal converted to chemical signal
      • Neurotransmitters released and convey message to next cell in pathway
    • Cells of the nervous system
      • Neuron
      • Neuroglia
    • Neuroglia
      Protect and support neurons
    • Neuroglia in the CNS
      • Ependymal cells
      • Astrocytes
      • Microglia
      • Oligodendrocytes
    • Ependymal cells
      • Simple ciliated cuboidal epithelium
      • Line fluid-filled cavities in brain (ventricles) and spinal canal
      • No basement membrane
    • Astrocytes
      • Named for their star-shape
      • Large, numerous glial cells
      • Form the blood-brain barrier
      • Regulate the chemical environment
    • Microglia
      • Named for their small size
      • Phagocytic capacity
      • Remove invading microbes and dead cells from CNS
    • Oligodendrocytes
      • Predominant neuroglia of white matter
      • Form myelin sheaths around all CNS axons
      • Provide structural and metabolic support
    • Neuroglia in the PNS
      • Satellite cells
      • Schwann cells
    • Schwann cells
      • Form myelin sheaths around PNS axons
      • Provide structural and metabolic support
      • Non-myelinated axons are enveloped in cytoplasm of Schwann cell
      • Myelinated axons are gradually wrapped by the Schwann cell membrane to create a myelin sheath
    • Satellite cells
      • Flattened cells that cover the surface of neuronal cell bodies
      • Provide structural and functional protection
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