classnotes11 - Note: We will not be following the book...

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Note: We will not be following the book exactly. Most of the material will be covered, but in a different order: 1) brief overview 2) anatomy and function of neurons 3) input - sensory apparatus (given time) 4) output (mostly muscles) 5) putting it all together - processing/integration/etc. Nervous system, overview: Purpose - to control/respond to the environment, internally or externally. Essentially, three steps (see also fig. 28.1A, p. 564): sensory --> processing (integration) --> motor output (usually) Physically, the nervous system is divided into: CNS - central nervous system (brain and spinal cord) PNS - peripheral nervous system (everything else) Some more terminology: nerve - bundle of neurons wrapped with connective tissue ganglion (plural = ganglia) - cluster of nerve (neuron) cell bodies (usually in PNS, but sometimes also considered to be in the CNS). Nervous system, part I - anatomy and function of neurons. Neurons have three basic parts [Fig. 28.2, p. 565] : 1) cell body - contains nucleus, etc. 2) dendrites - tree like structure that take the signal from the tips (of dendrites) to the cell. 3) axons - these can be very long and take the signal from the cell body to the end of the axon. Can have a variety of shapes, depending on the location. Supporting cells: myelin sheath - in the PNS this is formed by Schwann cells.
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- in the CNS this is formed by oligodendrocytes. - An example of their importance: multiple sclerosis causes deterioration of the myelin sheath, thus resulting in serious loss of coordination (we’ll examine the function of the myelin sheath shortly). astrocytes - maintain a blood/brain barrier. This prevents the passage of many substances into the brain, which ensures that a constant chemical environment is maintained. - they also offer support and nutrients to the neurons
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This note was uploaded on 07/21/2011 for the course BIO 101 taught by Professor Staff during the Spring '08 term at Northern Virginia Community College.

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classnotes11 - Note: We will not be following the book...

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