1. Nervous Tissue

2. Information Highways

3. Electrical Signals

4. 1600’s 1818

5. Signals Movement of charges (ions!)

6. Densely packed Tightly intertwined

7. Neurons Nerve cells Excitable Transmit signals Amitotic* Various shapes and sizes Extreme longevity Exceptionally high metabolic rate http://en.wikipedia.org/wiki/Li st_of_animals_by_number_of _neurons http://en.wikipedia.org/wiki/Li st_of_animals_by_number_of _neurons Neuroglia (glia) Supporting cells Smaller in size Undergo mitosis Outnumber neurons Split up into two types: – Scaffolding/insulation – Promoting health/growth

8. Support Cells of CNS Astrocytes - helps with exchanges between blood capillaries and neurons, forms the blood-brain barrier

9. Support Cells of CNS Microglia – monitors health, can transform into a microphage*

10. Support Cells of CNS Ependymal cells – lines central cavities of brain and spinal cord, formation of cerebrospinal fluid, ciliated – help move fluid

11. Support Cells of CNS Oligodendrocytes – composes myelin sheaths

12. Support Cells of PNS Satellite cells – function largely unknown Schwann cells – form myelin sheaths, vital to nerve fiber regeneration

13. Neurons