chapter 34 - Chapter 34: Integration and Control: The...

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Chapter 34: Integration and Control: The Nervous System I. Overview A. Function of the nervous system 1. monitoring internal and external environments a. CNS (central nervous system): brain and spinal cord. b. PNS (peripheral nervous system): motor and sensory neurons lying outside the CNS. 2. integration: filtering, processing, interpreting, comparing 3. response: motor outputs (PNS) to effectors-organs, glands and muscles 4. regulates and maintains homeostasis II. Structural and functional components of the NS A. Glia (neuroglia):most numerous nervous cell type 1. astrocytes: most abundant glial type 2. oligodendrocytes: form the myelin sheaths (covers axons) of the CNS 3. Schwann cells: form the myelin sheaths of the PNS B. Neurons: spiking and transmitting cells 1. long-lived, amitotic, and have a high metabolic rate 2. diversity of neuronal structures: See fig. 2 . 3. neuron types: sensory (afferent)long dendrite short axon carry message to CNS, motor (efferent) short dendrite long axon transmits signals to effectors, and interneurons connect neuron to neuron C. Neurons : Generating and conducting electrical impulses or signals 1. dendrites-receive information from another cell and transmit the message to the cell body(closer to cell body or soma the more influential it is)/ axon-receive information from another cell and transmit the message to the cell body; axon terminal=buton/ axon hillock- beginning of axon where it first comes out of soma a. “resting” membrane potential. –normal cells in body before any signals are sent to it or anything is occuring b. distribution of ions across cell membrane-Na+ outside cell, K+ inside cell c. Na+/K+ pump=constantly moves ions against concentration gradient d. ion leak channels=allow K+ to leak out of a cell e. large macromolecules-account for negativity of inside of cell f. electrochemical equilibrium-resting membrane potential 2. Graded potentials. Fig. 9 . a. Depolarizations (EPSPs)-Na+ comes into cell, cell becomes more positive, excititory b. Hyperpolarizations (IPSPs)-K+ flows out of cell, cell inside becomes more negative, inhibitory c. ligand (or chemically)-gated channels d. Graded potentials are typical of dendrites and somas-brief caused by nuerotrasmitters and correlated w/ neurotransmitter time span
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This note was uploaded on 04/26/2009 for the course BCOR 1010 taught by Professor Latier,jef during the Fall '07 term at Colorado.

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chapter 34 - Chapter 34: Integration and Control: The...

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