nervous3 - Nervous system, integration: Overview, and...

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Nervous system, integration: Overview, and peripheral nervous system: Some review & misc. parts [Fig., not in text] : - white matter --> looks white due to the myelinated sheaths, which are quite fatty. - gray matter --> consists mostly of nerve cell bodies, dendrites, and axons without fatty sheath. - ventricles --> spaces in the CNS that contain cerebrospinal fluid. This moves nutrients, hormones and other substances around, and, particularly in the brain acts as a shock absorber. - meninges [Fig., not in text] : - nervous tissue generally has the consistency of watery jello. It’s very fragile. - meninges surround the nervous tissue and help maintain the structural integrity; they also allow for cerebrospinal fluid to circulate. Consists of: an outer covering, the dura mater a space in between made up of cerebrospinal fluid and the arachnoid membrane an inner membrane lying right over the brain, the pia mater The PNS, or Peripheral Nervous System: consists of paired spinal nerves and paired cranial nerves [Fig. 49.4, p. 1066]. - each set comes/goes to different structures. Except for a few cranial nerves (e.g. optic nerve), each set contains both sensory and motor components. The PNS is divided into two broad groups [Fig. 49.7, p. 1068] : 1) Somatic - sensory and motor nerves, generally parts that you have voluntary control over and that sense the external environment. 2) autonomic - generally non-voluntary. Nerves that serve the internal organs. Divided into three parts, but let's skip these details. Finally, how does all this work and fit together? Example: reflex arc [Fig. 49.3, p. 1066] : sensory neuron --> CNS --> motor neuron
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A reflex is a response that does not involve the brain. But - you can feel the response. So the signal does eventually get to the brain. Reflex arc. What happens to signal as it does go to the brain? - there are two pathways that lead to the brain. Both cross over to the other side as follows [Fig., not in book] : - sensory neuron --> thalamus --> sensory cortex [Fig., not in text] - thalamus — coordinates information coming from different parts
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This note was uploaded on 04/29/2009 for the course BIOL 303 taught by Professor Birchard during the Spring '08 term at George Mason.

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nervous3 - Nervous system, integration: Overview, and...

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