Cells of the Nervous System

1

• Cells of the Nervous System
• Neurons
• Motor neurons (efferent)

Node of Ranvier
2

• Cells of the Nervous System
• Neurons
• Motor neurons (efferent)
• Sensory neurons (afferent)

3

• Cells of the Nervous System
• Neurons
• Motor neurons (efferent)
• Sensory neurons (afferent)
• Interneurons

aka interneuron or intrinsic neuron
4

• Cells of the Nervous System
• Neurons
• Glia

• Astrocyte (Astroglia) Star-shaped cells that
  provide physical and nutritional support for
  neurons
• clean up brain debris
• transport nutrients to neurons
• hold neurons in place
• digest parts of dead neurons
• regulate content of extracellular space.
• Microglia Like astrocytes, microglia digest
  parts of dead neurons.
• Oligodendrocytes Provide the insulation
  (myelin) to neurons in the central nervous
  system.
• Schwann Cells Provide the insulation (myelin)
  to neurons in the peripheral nervous system.

Source http//faculty.washington.edu/chudler/glia
.html
5

• Cells of the Nervous System
• Neurons
• Glia
• Differences between neurons glia

• Neurons have TWO processes called axons and
  dendrites....glial cells have only ONE.
• Neurons CAN generate action potentials...glial
  cells CANNOT. However, glial cells do have a
  resting potential.
• Neurons HAVE synapses that use
  neurotransmitters...glial cells do NOT have
  chemical synapses.
• There are many MORE (10-50 times more) glial
  cells in the brain compared to the number of
  neurons.

Source http//faculty.washington.edu/chudler/glia
.html
6
II. Nerve Impulse A. Resting Potential
Negative inside, relative to the outside -70mv.
And the sodium-potassium pump keeps it that way.
7
II. Nerve Impulse A. Resting Potential B.
Action Potential
-70mv
30mv
30mv
-80mv
-70mv
Depolarization (internal electrical charge moving
toward a positive charge)
Hyperpolarization (internal electrical charge
moving more negatively, past the resting
potential)
Animation
Channel gating
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II. Nerve Impulse A. Resting Potential B.
Action Potential C. Saltatory Conduction