Non-Neuronal Cells of the Nervous System

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Non-Neuronal Cells of the Nervous System

• Neuroglia
• Cant generate
• or transmit nerve
• impulses (signals)

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Non-Neuronal Cells of the Nervous System
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Central Nervous System (4 kinds of cells)

• 1) Astrocytes
• Provides neurons with
• nutrients energy
• Physical support
• Forms the BloodBrain
• Barrier

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• 2) Oligodendrocytes
• Secretes myelin sheaths
• around the axon of
• the neurons (this
• directs impulse)

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• 3) Microglia
• Are like Macrophages
• Scavenge cell debris
• Protects from
• pathogens in the brain

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• 4) Ependymal Cells
• Line the hollow cavities
• (ventricles)
• Secretes cerebral spinal
• fluid which acts as
• shock absorber, and distributes
  nutrients
• in the brain and spinal cord

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Central Nervous System
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• A myelin system
• Protects cells

Peripheral Nervous System
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Transmission Of the Nerve Impulse
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Before arrival of an Action (Electric) Potential
Synapse (2 cells)
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Action Potential opens channels that
cause Calcium ions to move into the Synaptic Bulb
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Vesicles fuse to the Synaptic Membrane
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Neurotransmitters released into cleft

• Examples
• Glutamate (most common in brain)
• Gamma-aminobutyric acid (GABA)
• Dopamine
• Acetylcholine
• Epinephrine
• Histamine
• Serotonin
• Neurotensin
• Nitric Oxide
• Neuropeptide Y

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Neurotransmitters bind to receptors in next
neuron...opening Sodium channels.
This initiates an Action Potential in the
next Neuron.
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Neurotransmitters are cleared out of cleft.

• By
• Diffusion
• Reuptake by upper neuron
• Enzymatic breakdown