1. An introduction to the cells & structures of your nervous system.
Basic Neuroanatomy
An introduction to the cells & structures of your nervous system.

2. Overview of the system Central Nervous System = Brain & Spinal cord
Peripheral Nervous System = Nerves & Ganglia

3. Nerves Bundles of Neurons, coated with protective tissues.
1 bundle = a fascicle
Thousands of cells in a single nerve.

4. Motor Neurons Soma Dendrites Axon Terminal fibres Motor end plates
Myelin Sheath

5. Motor Neurons Myelin = protective protein Made by Schwann cells
Wrap around axon
Prevent ‘cross-talk’

6. Motor Neurons
Motor neurons stimulate muscle cells.

7. Sensory Neurons Basic elements same, but Soma is mid-way in cell
Creates incoming Dendron (connects to a sensory receptor) & outgoing Axon (connects to another neuron)
Bipolar Neuron

8. Sensory Neurons
All sensory neurons connect to a specific sensory receptor & send their messages to the CNS for interpretation & response.

9. Sensory Neurons
Image of Sensory Neuron in human skin:

10. Interneurons Also called Multipolar Neurons Short, small cells
Connect Sensory & Motor neurons
Found in Ganglia, Spinal Cord & Brain

11. Some images of Interneurons:

12. Support Cells: Neuroglia
Glial Cells
Four types in CNS
(Astroglia, Microglia, Oligodendrocytes, & Ependymal cells.)
Maintain ion balance; connect to blood vessels; protect soma by ‘padding’ it; some ‘clean up’ by phagocytosis; produce myelin…
PNS Schwann Cells

13. Review of all 3 types:

14. PNS Innervation
Nerves are either excitatory or inhibitory to our organs.
Sympathetic = “Fight or Flight”
Thoracolumbar
Parasympathetic = “Rest & Digest”
Craniosacral

15. The Reflex Arc Fast Instinctual
Mediated by the Spinal Cord, not the Brain
Involves all three neurons

16. The Reflex Arc
At the level of the spinal cord, the reflex is very specific:
Sensory goes into the upper, or Dorsal ganglion
Motor exits via Ventral ganglion

17. The Reflex Arc

18. The Reflex Arc
Sneezing is a reflex!

19. The Reflex Arc
Some reflexes can be suppressed…