Nervous

• Central Nervous System


  Brain and Spinal Cord

  
• Peripheral Nervous System

  Ganglia, Cranial and Spinal Nerves

  
• Neuron types in CNS

  • Mostly multipolar

  
• Glia in CNS

  • Oligodendrocytes
  • Astrocytes
  • Microglia
  • Ependymal cells

  
• Neuron types in PNS

  • Pseudounipolar (+ bipolar & multipolar)
• Glia in PNS

  • Schwann cells
  • Satellite cells
• Grey matter

  Neuronal cell bodies, dendrites, axons and associated glia/support cells
• White matter

  Axons (mostly myelinated) and associated glia
• Cell types of the NS

  • Neurons (functional cells)
  • Astrocytes
  • Schwann cells (PNS)
  • Oligodendrocytes
  • Microglia
  • Ependymal cells
  • Satellite cells (PNS)

  
• Neurons


  • Very big cell body with a prominent nucleolus, vesicular/euchromatic nucleus & nissl bodies (Rough ER)
  • Processes: dendrites -> receptive region & axons -> output region

  
• Structural classification of neurons

  • Multipolar: have one axon and two or more dendrites
  • Bipolar: with one dendrite and one axon
  • Pseudounipolar: have a single process that bifurcates close to the soma, with the peripheral branch extending to the periphery and the central branch other toward the CNS.
• Functional classification of neurons

  • Afferent: Sensory (generally unipolar/pseudounipolar)
  • Efferent: Motor (mostly multipolar)
  • Interneurons: (generally multipolar)

  
• Support cells (glia) - Oligodendrocytes

  Small cells with rounded, condensed nuclei and unstained cytoplasm, produce myelin sheath in CNS
• Support cells(glia) - Astrocytes

  Most numerous, control of signal propagation and synapse formation, maintenance of ionic and transmitter metabolism, component of blood-brain barrier, involved in brain repair
• Support cells (glia) - Ependymal cells

  Low columnar or cuboidal cells that line ventricles of brain and central canal of spinal cord, function: CSF production and secretion

  
• Support cells (glia) - Microglia

  They have short irregular processes and rod shaped nuclei, evenly distributed throughout the white and grey matter, capable of migrating, specialized phagocytes, immune effector cells, phagocytic
• Support cells(glia) - Schwann cells

  Myelination in PNS, one Schwann cell myelinates one part of axon
• Support cells (glia) - Satellite cells

  Exert a trophic or supportive effect on neurons, insulating, nourishing, and regulating their microenvironments
• Anterior Horn Cell

  Efferent (motor) neuron, multipolar
• Spinal Ganglion/DRG Cell

  Afferent (sensory) neuron, pseudounipolar

  
• Endoneurium

  Loose connective tissue surrounding each individual nerve fibre
• Perineurium

  Specialized connective tissue surrounding each nerve fascicle
• Epineurium

  Dense irregular connective tissue that surrounds a peripheral nerve and fills the spaces between nerve fascicles
• Nerve fibres occur in other organs (among other tissues) besides the nervous system
• Myelinated fibers have nodes of Ranvier between segments of myelin sheath