Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  1)  2)  3)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  1) Sensory input   2) Integration   3) Motor output 

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functions of the Nervous System  1) Sensory input  Gathering information (stimuli) inside & outside body  2) Integration  Processing sensory input  “Deciding” if action is needed  3) Motor output  Response activates effectors, muscles or glands

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of the Nervous System  Central nervous system (CNS)   Peripheral nervous system (PNS) 

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Structural Classification of the Nervous System  Central nervous system (CNS)   Peripheral nervous system (PNS)  Where are they?

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the PNS  Sensory  Motor

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the PNS  Sensory  Motor What do they do?

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the PNS  Sensory (afferent) division  Motor (efferent) division 

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the PNS  Sensory (afferent) division— (receptor  CNS)  Motor (efferent) division— (CNS  effectors)  Somatic NS  Autonomic NS

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the PNS  Sensory (afferent) division— (receptor  CNS)  Motor (efferent) division— (CNS  effectors)  Somatic NS = voluntary  Autonomic NS = involuntary

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the PNS  Sensory (afferent) division— (receptor  CNS)  Motor (efferent) division— (CNS  effectors)  Somatic NS = voluntary  Autonomic NS = involuntary  Sympathetic NS  Parasympathetic NS

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of the PNS  Sensory (afferent) division— (receptor  CNS)  Motor (efferent) division— (CNS  effectors)  Somatic NS = voluntary  Autonomic NS = involuntary  Sympathetic NS— “fight or flight”  Parasympathetic NS--resting

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organization of the Nervous System Central Nervous system Peripheral Nervous system Nervous system

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organization of the Nervous System Figure 7.2 Central Nervous system Peripheral Nervous system Nervous system Motor (efferent) Sensory (afferent)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organization of the Nervous System Figure 7.2 Central Nervous system Peripheral Nervous system Nervous system Motor Sensory Autonomic Nervous system Motor (efferent) Sensory (afferent) Somatic Nervous system (voluntary) Autonomic Nervous system (involuntary)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Organization of the Nervous System Figure 7.2 Central Nervous system Peripheral Nervous system Nervous system Motor Sensory Somatic Nervous system (voluntary) Autonomic Nervous system (involuntary) Sympathetic Nervous system (fight or flight) Paraympathetic Nervous system (resting) Motor (efferent) Sensory (afferent)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Figure 7.4

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

Terminal bud

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

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Nucleolus Nucleus Axon hillock

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Nucleolus Nucleus Axon hillock

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons = nerve cells  Specialized to transmit messages  Cell body   Processes  Irritability—ability to respond to stimuli Conductivity—ability to transmit an impulse

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons = nerve cells  Specialized to transmit messages  Cell body—nucleus (w/ large nucleolus), metabolic center  Nissl substance  Neurofibrils  Processes—fibers that extend from the cell body  Dendrites  Axons

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Neurons = nerve cells  Specialized to transmit messages  Cell body—nucleus (w/ large nucleolus), metabolic center  Nissl substance--Specialized RER  Neurofibrils--Intermediate cytoskeleton holds shape  Processes—fibers that extend from the cell body  Dendrites—conduct impulses toward the cell body  Axons—conduct impulses away from the cell body

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells-“neuroglia”  Astrocytes .  Microglia  Ependymal cells.  Oligodendrocytes.  Satellite cells  Schwann cells

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Support Cells—Astrocytes Figure 7.3a Astrocytes—“ star cells”

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.3a Astrocytes—“ star cells” Support Cells—Astrocytes

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Support Cells—Microglia Figure 7.3b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells Figure 7.3c CNS!

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Support Cells—Ependymal cells Figure 7.3c (ventricle of the brain)

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

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Support Cells—Schwann cells (dark ring xc) Figure 7.3e PNS!

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells-“neuroglia”  Astrocytes .  Microglia  Ependymal cells.  Oligodendrocytes.  Satellite cells  Schwann cells

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Support Cells-“neuroglia”  Astrocytes—Abundant, star-shaped cells brace neurons  Barrier for capillaries & neurons, control chemical environment of brain  Microglia—Spiderlike phagocytes dispose of debris  Ependymal cells —Line cavities of the CNS, circulate cerebrospinal fluid (CSF)  Oligodendrocytes —Wrap around nerve fibers in CNS, produce myelin sheaths  Satellite cells —Protect neuron cell bodies  Schwann cells —Form myelin sheath in the PNS

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nervous Tissue: Special features of neurons  Terminal buds  Synaptic cleft  Synapse  Myelin sheath  Nodes of Ranvier Axon terminal Vesicles Synaptic cleft Action potential arrives Synapse Axon of transmitting neuron Receiving neuron

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings  Terminal buds contain vesicles w/ neurotransmitters  Synaptic cleft—gap between adjacent neurons  Synapse—junction between nerves  Myelin sheath—white, fatty material covering axons  Nodes of Ranvier—gaps in myelin sheath along axon Nervous Tissue: Special features of neurons

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.5 Nervous Tissue: Special features of neurons

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neuron Cell Body Location  Most cell bodies are found in the CNS  Gray matter—cell bodies and unmyelinated fibers  Nuclei—cell bodies in the white matter of the CNS  Ganglia—collections of cell bodies outside the central nervous system The rest of white matter is myelinated axons

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Sensory (afferent) neurons   Interneurons (association neurons)   Motor (efferent) neurons 

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Sensory (afferent) neurons   Interneurons (association neurons)   Motor (efferent) neurons  What do they do?

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Functional Classification of Neurons  Sensory (afferent) neurons Carry impulses  CNS from:  outside (cutaneous sense organs),  or inside (proprioceptors—detect stretch / tension)  Interneurons (association neurons)  Form neural pathways in the CNS  Connect sensory and motor neurons  Motor (efferent) neurons  Carry impulses from CNS  organs/muscles/glands

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Sensory nerve endings Figure 7.7

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Sensory nerve endings Figure 7.7 Afferent!

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

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.8a Structural Classification of Neurons  Neurons may be:  Multipolar  Bipolar  Unipolar

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.8a Structural Classification of Neurons  Neurons may be:  Multipolar  Bipolar  Unipolar How are they shaped?

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Figure 7.8a Structural Classification of Neurons  Multipolar neurons—many extensions from the cell body  Bipolar neurons—one axon and one dendrite Several dendrites, only one axon!

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

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 One of both!

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1)  2)  3)  4)  5)  6)  7)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1) Resting neuron receives stimulus  2)  3)  4)  5)  6)  7)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1) Resting neuron receives stimulus  2) Na + gates open, Na + ions enter cell  3)  4)  5)  6)  7) Na +

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1) Resting neuron receives stimulus  2) Na + gates open, Na + ions enter cell  3) Membrane depolarizes  4)  5)  6)  7) Na +

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1) Resting neuron receives stimulus  2) Na + gates open, Na + ions enter cell  3) Membrane depolarizes  4) Depolarization spreads down axon  5)  6)  7) Na +

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1) Resting neuron receives stimulus  2) Na + gates open, Na + ions enter cell  3) Membrane depolarizes  4) Depolarization spreads down axon  5) K + gates open, K + ions leave cell  6)  7) Na + K+K+

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1) Resting neuron receives stimulus  2) Na + gates open, Na + ions enter cell  3) Membrane depolarizes  4) Depolarization spreads down axon  5) K + gates open, K + ions enter cell  6) Membrane repolarizes—returns to resting state  7) Na + K+K+

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Conduction of nerve Impulses  1) Resting neuron receives stimulus  2) Na + gates open, Na + ions enter cell  3) Membrane depolarizes  4) Depolarization spreads down axon  5) K + gates open, K + ions enter cell  6) Membrane repolarizes—returns to resting state  7) Na + /K+ pump replaces ions Na + K+K+ K+K+ K+K+

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Change in membrane potential

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Change in membrane potential Na + gates open K + gates open Na+/K+ pump restores original concentrations

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Nerve Impulses  Resting neuron has negative charge inside  Depolarization—becomes less negative inside as Na + enter  This causes an action potential in the neuron  If it starts, it is propagated over the entire axon  Impulses travel faster when fibers have myelin sheath  Repolarization  K + rush out after Na + rush in, repolarizing membrane  Na + /K+ pump, using ATP, restores original configuration

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 Remember what happens at the neuromuscular junction? A very similar process occurs at the neuron-neuron junction

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

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 vesicles are released from the axon terminal  The dendrites of the next neuron has receptors for the neurotransmitter  An action potential is started in the dendrite

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 Synapse Axon of transmitting neuron Receiving neuron

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neurotransmitters Figure 7.10, step 1 Acetylcholineexcitatory. Dopamineusually inhibitory. GABAmajor inhibitory Glutamatemost common excitatory Glycineinhibitory Norepinephrineusually excitatory, Serotonin inhibitory

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neurotransmitters Figure 7.10, step 1 Acetylcholineexcitatory. Dopamineusually inhibitory. GABAmajor inhibitory Glutamatemost common excitatory Glycineinhibitory Norepinephrineusually excitatory, Serotonin inhibitory

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neurotransmitters Figure 7.10, step 1 Excitatory : Inhibitory : or

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neurotransmitters Figure 7.10, step 1 Excitatory : a) makes the neuron more likely to start an action potential Inhibitory : a) makes the neuron less likely to start an action potential or

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Neurotransmitters Figure 7.10, step 1 Excitatory : a) makes the neuron more likely to start an action potential b) Depolarizes the membrane Inhibitory : a) makes the neuron less likely to start an action potential b) Hyperpolarizes the membrane or

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

Nerve Impulses Figure 7.9a–b

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

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

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

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

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

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

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

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

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