1. Histology of Nervous Tissue Martini Chapter 12
Lab Activity 12
Histology of Nervous Tissue
Martini Chapter 12
Portland Community College
BI 231

2. Neuron

3. Myelin
Multilayered lipid and protein covering formed by Schwann cells around axons
Oligodendrocytes in the CNS
The covering is the plasma membrane of the Schwann Cell
The Schwann Cell can cover more than one axon
Insulates axon

4. Nodes of Ranvier
Areas between Schwann Cells that do not contain Myelin
Involved in saltatory conduction

5. Dendrite
Neuron Cell Body
Nucleus
Axon Hillock
Axon

6. Axon Terminal (Synaptic end bulbs)
Schwann Cell
Axon
Node of Ranvier
Myelin Sheath
Telodendria
Axon Terminal (Synaptic end bulbs)

7. Unipolar Neuron All are sensory afferent
Dendrite (trigger zone)
Axon
Cell Body
All are sensory afferent
Cell bodies are located in the dorsal root ganglia

8. Bipolar Neuron Location: special senses (smell, vision, hearing)
Dendrite (trigger zone)
Axon
Cell Body
Location: special senses (smell, vision, hearing)

9. Multipolar Neuron Most common type of neuron
Cell Body
Axon
Dendrites (trigger zone)
Most common type of neuron
Interneurons and motor neurons

10. Motor (Efferent) Neurons Efferent = Away from CNS
These are neurons that carry information from CNS to the body
Groups of axons running together are the Nerves when they are outside the CNS and Tracts inside the brain and spinal cord
The cell bodies are clustered in groups in the CNS and are called nuclei
Brain gray matter is made up of millions of nuclei.
It is gray because there is no myelin around the cell bodies
These axons exit the spinal cord on the ventral side

11. Sensory (Afferent) Neurons Afferent = Toward the CNS
These carry sensory information from the body to the CNS (brain and spinal cord)
Their axons run in the same group as the motor neurons (nerves=groups of axons)
Their cell bodies are clustered outside of the spinal cord and are called ganglia
These axons enter the spinal cord on the dorsal side

12. Association or Interneurons
Neurons between the afferent and efferent neurons.
Are only in the CNS

13. Neuron Perineurium Fascicle Epineurium Axon Myelin Sheath
Node of Ranvier
Perineurium
Fascicle
Epineurium

14. Glial Cells Associated with neurons Provide Supportive scaffolding
Segregate and insulate neurons
Outnumber neurons by 10 to 1

15. Supporting Cells in the CNS Astrocytes
Star Shaped
Many functions
Control the chemical environment around neurons by buffering K+ and NT
Exchanges between capillaries and neurons (blood-brain barrier)
Nutrient transfer

16. Supporting Cells in the CNS Oligodendrocytes
Oligodendrocytes produce the myelin sheath which provides the electrical insulation for some neurons in the CNS

17. Supporting Cells in the CNS Microglia
Small oval cells with long thorny processes
Monitor the health of neurons
Specialized immune cells that phagocytize microorganisms and debris
Immune system cells do not have access to CNS

18. Supporting Cells in the PNS Schwann Cells
Form the myelin sheath around axons in the PNS

19. Schwann Cell

20. The End
The End