1. CNS- brain, spinal cord. PNS – spinal nerves, cranial nerves, ganglia, sensory receptors. 2. Excitable cells – conduct nerve impulses. Support cells- support. 3. Sensory- sense, Integration- make decisions, motor- output. 4. Soma- contain nissl bodies which synthesis protein. Dendrites- Receptive input region, conduct graded potentials toward the CNS. Axon conduct action potentials away from soma. 5. Multipolar- many dendrites and one axon. Bi polar- one dendrite and one axon. Unipolar – T like in ganglia found in pns. 6. Astrocytes- control chemical environment around neurons. Oligodendcytes- form myelin sheath around several axons. Ependymal cells- circulate cerebrospinal fluid, ciliated epithelial cells that line the cavities of the brain and spinal cord. Microglia eats microorganisms or neuronal debris. 7. Schwann cells- produce myelin sheath around 1 axon. Satellite cells 8. Deterioration of myelin sheath 9. Non myelinated 10. Myelinated 11. A.-Voltage difference across plasma membrane
B. – Unequal distribution of ions across the plasma membrane
C. – sodium potassium pump 12. Threshold stimulus- weakest stimulus capable of production a response in an excitable tissue. Action potential- Long distance signals of axons. 13. All or none, self propagateing, not graded, travel short or long distance with losing strength, travel in one direction.
14 inside of cell becomes more positive
15. inside of cell