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Chapter 12 Nervous Tissue. Functional composition of the PNS. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.17.

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Presentation on theme: "Chapter 12 Nervous Tissue. Functional composition of the PNS. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.17."— Presentation transcript:

1 Chapter 12 Nervous Tissue

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3 Functional composition of the PNS. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.17

4 A closer look at the (often antagonistic) divisions of the autonomic nervous system (ANS). Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.18

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6 Functions of the Nervous System Sensory Motor Integrative / association

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11 Neuroglia Astrocytes Microglia Ependymal Cells Oligodendrocytes Schwann Cells Satellite cells

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15 Found in the CNS only

16 Schwann cells are found within the PNS.  Form a myelin sheath by insulating axons. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.5

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21 Measuring Membrane Potentials. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.6a  An unstimulated cell usually have a resting potential of -70mV.

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26 The Action Potential: All or Nothing Depolarization.  If graded potentials sum to  -55mV a threshold potential is achieved. This triggers an action potential.  Axons only. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.8c

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31 Saltatory conduction.  In myelinated neurons only unmyelinated regions of the axon depolarize. Thus, the impulse moves faster than in unmyelinated neurons. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.11

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33 Words to Know Wallerian degeneration Multiple sclerosis Epilepsy Neuropathy Guillain-Barre Syndrome Rabies

34 Summation: graded potentials (EPSPs and IPSPs) are summed to either depolarize or hyperpolarize a postsynaptic neuron. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig. 48.14

35 Acetylcholine.  Excitatory to skeletal muscle.  Inhibitory to cardiac muscle.  Secreted by the CNS, PNS, and at vertebrate neuromuscular junctions. 6. The same neurotransmitter can produce different effects on different types of cells Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

36 Biogenic Amines.  Epinephrine and norepinephrine. Can have excitatory or inhibitory effects. Secreted by the CNS and PNS. Secreted by the adrenal glands. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

37 Dopamine  Generally excitatory; may be inhibitory at some sites. Widespread in the brain. Affects sleep, mood, attention, and learning.  Secreted by the CNS and PNS.  A lack of dopamine in the brain is associated with Parkinson’s disease.  Excessive dopamine is linked to schizophrenia. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

38 Serotonin.  Generally inhibitory. Widespread in the brain. Affects sleep, mood, attention, and learning  Secreted by the CNS. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings


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