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PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing.

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Presentation on theme: "PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing."— Presentation transcript:

1 PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PART A 7 The Nervous System

2 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  Sensory input—gathering information  To monitor changes occurring inside and outside the body  Changes = stimuli  Integration  To process and interpret sensory input and decide if action is needed

3 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  Motor output  A response to integrated stimuli  The response activates muscles or glands

4 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System Figure 7.1

5 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of the Nervous System  Central nervous system (CNS)  Brain  Spinal cord  Peripheral nervous system (PNS)  Nerves outside the brain and spinal cord  Spinal nerves  Cranial nerves

6 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the Peripheral Nervous System  Sensory (afferent) division  Nerve fibers that carry information to the central nervous system  Motor (efferent) division  Nerve fibers that carry impulses away from the central nervous system

7 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organization of the Nervous System Figure 7.2

8 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the Peripheral Nervous System  Motor (efferent) division (continued)  Two subdivisions  Somatic nervous system = voluntary  Autonomic nervous system = involuntary

9 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Support cells in the CNS are grouped together as “neuroglia”  Function: to support, insulate, and protect neurons

10 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Astrocytes  Abundant, star-shaped cells  Brace neurons  Form barrier between capillaries and neurons  Control the chemical environment of the brain

11 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3a

12 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Microglia  Spiderlike phagocytes  Dispose of debris

13 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3b

14 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Oligodendrocytes  Wrap around nerve fibers in the central nervous system  Produce myelin sheaths

15 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3d

16 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells  Satellite cells  Protect neuron cell bodies  Schwann cells  Form myelin sheath in the peripheral nervous system

17 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3e

18 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Neurons = nerve cells  Cells specialized to transmit messages  Major regions of neurons  Cell body—nucleus and metabolic center of the cell  Processes—fibers that extend from the cell body

19 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Cell body  Nissl substance  Specialized rough endoplasmic reticulum  Neurofibrils  Intermediate cytoskeleton  Maintains cell shape

20 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons Figure 7.4

21 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Cell body  Nucleus  Large nucleolus  Processes outside the cell body  Dendrites—conduct impulses toward the cell body  Axons—conduct impulses away from the cell body

22 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons Figure 7.4

23 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Axons end in axonal terminals  Axonal terminals contain vesicles with neurotransmitters  Axonal terminals are separated from the next neuron by a gap  Synaptic cleft—gap between adjacent neurons  Synapse—junction between nerves

24 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons  Myelin sheath—whitish, fatty material covering axons  Schwann cells—produce myelin sheaths in jelly roll–like fashion  Nodes of Ranvier—gaps in myelin sheath along the axon

25 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons Figure 7.5

26 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Cell Body Location  Most neuron cell bodies are found in the central nervous system  Gray matter—cell bodies and unmyelinated fibers  Nuclei—clusters of cell bodies within the white matter of the central nervous system  Ganglia—collections of cell bodies outside the central nervous system

27 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Sensory (afferent) neurons  Carry impulses from the sensory receptors to the CNS  Cutaneous sense organs  Proprioceptors—detect stretch or tension  Motor (efferent) neurons  Carry impulses from the central nervous system to viscera, muscles, or glands

28 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Interneurons (association neurons)  Found in neural pathways in the central nervous system  Connect sensory and motor neurons

29 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Classification Figure 7.6

30 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.8a Structural Classification of Neurons  Multipolar neurons—many extensions from the cell body

31 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of Neurons  Bipolar neurons—one axon and one dendrite Figure 7.8b

32 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of Neurons  Unipolar neurons—have a short single process leaving the cell body Figure 7.8c

33 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Properties of Neurons  Irritability  Ability to respond to stimuli  Conductivity  Ability to transmit an impulse

34 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses  Resting neuron  The plasma membrane at rest is polarized  Fewer positive ions are inside the cell than outside the cell  Depolarization  A stimulus depolarizes the neuron’s membrane  A depolarized membrane allows sodium (Na+) to flow inside the membrane  The exchange of ions initiates an action potential in the neuron

35 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses Figure 7.9a–b

36 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses  Action potential  If the action potential (nerve impulse) starts, it is propagated over the entire axon  Impulses travel faster when fibers have a myelin sheath

37 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses Figure 7.9c–d

38 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses  Repolarization  Potassium ions rush out of the neuron after sodium ions rush in, which repolarizes the membrane  The sodium-potassium pump, using ATP, restores the original configuration

39 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses Figure 7.9e–f

40 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses  Impulses are able to cross the synapse to another nerve  Neurotransmitter is released from a nerve’s axon terminal  The dendrite of the next neuron has receptors that are stimulated by the neurotransmitter  An action potential is started in the dendrite

41 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Neurotransmitter broken down and released Ion channel opensIon channel closes

42 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 1 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron

43 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 2 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Vesicle fuses with plasma membrane Synaptic cleft Ion channels Receiving neuron Transmitting neuron

44 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 3 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron

45 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 4 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron

46 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 5 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Ion channel opens

47 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 6 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Neurotransmitter broken down and released Ion channel opensIon channel closes

48 Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Transmission of a Signal at Synapses Figure 7.10, step 7 Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron Neurotrans- mitter is re- leased into synaptic cleft Neurotrans- mitter binds to receptor on receiving neuron’s membrane Vesicle fuses with plasma membrane Synaptic cleft Neurotransmitter molecules Ion channels Receiving neuron Transmitting neuron Receptor Neurotransmitter Na + Neurotransmitter broken down and released Ion channel opensIon channel closes


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