1. Neurons & Glia Lesson 8

2. Nature of the Nervous System n Golgi & Cajal shared Nobel Prize (1906) n Reticular Theory l Camillo Golgi n The Neuron Doctrine l Santiago Ramon y Cajal Silver chromate l Golgi Stain ~

3. Neurons n Basic functional unit of N.S. l Specialized cell l All cells have same basic properties n Regulation of behavior n Information processing l Transmits l Integrates l Stores ~

4. n Dendrites & Soma l Receives & Integrates information l electrical signal within ~

5. n Axon carries information away from soma l Electrical signal within l Axon terminal releases chemical message ~

6. By function (connections) Neuron Classification

7. By Morphology n # of neurites l Multipolar, bipolar, monopolar n By Dendrite Structure l Pyramidal l Stellate n Dendritic Spines l Spiny or Aspinous ~

8. Unipolar BipolarMultipolar By morphology (# of neurites)

9. By Axon Diameter n Sensory afferents l Size: largest  smallest A , A , A , C n C: small, unmyelinated l pain & temperature A  : l not associated with skin receptors l proprioceptors in muscle ~

10. Primary Afferents n Conduction speed l larger faster & l myelinated faster~

11. Other Classification Schemes n Axon length l Golgi Type I - long l Golgi Type II - short (local signaling) n Chemistry l neurotransmitter released l e.g., cholinergic, dopaminergic ~

12. Neurons vs. Nerves n Neurons - cells l microscopic n Nerves - bundles of axons l seen with naked eye ~

13. Astrocytes n Provide physical support n Regulating chemical content of extracellular fluid l localizes neurotransmitters l K+ concentration n Blood-brain Barrier ~ Glia

14. Brain Capillary Blood-Brain Barrier Typical Capillary astrocytes

15. BBB: Function n Maintains stable brain environment l large fluctuations in periphery n Barrier l to poisons l neurotransmitters & other chemicals n Regulates nutrient supplies l glucose levels l active transport ~

16. Myelin n Wrap around axon n Saltatory Conduction l faster transmission n CNS: oligodendroglia or oligodendrocytes n PNS: Schwann cells ~

17. Other non-neuronal cells n Microglia l phagocytosis l immune-like function n Ependymal cells l line walls of ventricles l develop from radial glia ~