Nervous System

Nervous System - Chapter 38 Outline The Nervous system 38.1 What Are the Structures and Functions of Neurons p 762 38.2 How Is Neural Activity

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Chapter 38 Outline The Nervous system 38.1 What Are the Structures and Functions of Neurons? p. 762 38.2 How Is Neural Activity Produced and Transmitted? p. 762 38.3 How Are Nervous Systems Organized? p. 764 38.4 What Is the Structure of the Human Nervous System? p. 770 38.5 How Does the Brain Produce the Mind? p. 776
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Chapter 38 Outline Continued… 38.6 How Do Sensory Receptors Work? p. 781 38.7 How Are Mechanical Stimuli Detected? p. 782 38.8 How Is Sound Sensed? p. 782 38.9 How Is Light Sensed? p. 785 38.10 How Are Chemicals Sensed? p. 788
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Section 38.1 Outline 38.1 What Are the Structures and Functions of Neurons?
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Neurons Neurons (nerve cells) must perform four specialized functions Receive information Integrate information Conduct signals over distances Transmit signals to other neurons, tissues, or organs
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Neurons Typical neurons have four distinct structural regions Dendrites The cell body The axon Synaptic terminals
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Neurons Dendrites Branched cell body extensions Receive information from surrounding neurons and sensory receptors
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Neurons The cell body Integrates incoming information from dendrites If incoming signals are positive enough, an action potential (electrical output signal) forms
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Neurons The axon Conducts electrical signals to the synaptic terminal Often covered in myelin to speed electric transmission Often bundled together to form nerves
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Neurons The synaptic terminal Branched endings of axons Most contain neurotransmitters A specific chemical released under the stimulus of an action potential Forms synapses with other cells Site at which the neuron communicates with other cells, tissues, or organs
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Section 38.2 Outline 38.2 How Is Neural Activity Produced and Transmitted? Neurons Produce Electrical Voltages Across Their Membranes Neurons Communicate at Synapses
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Electrical Voltages Most neurons have a negative resting potential Describes the resting neuron membrane potential Ranges from -40 to -90 millivolts (mV) Negative value indicates that the cell interior is more negative than the exterior
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Electrical Voltages If the membrane potential becomes less negative, reaching a threshold value The neuron will generate an action potential Membrane potential rises rapidly to +50 mV, then returns to resting potential The action potential signal flows down axon to synaptic terminals, where cell communication occurs
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Synapses Neurons communicate at synapses The presynaptic neuron Transmits a signal by releasing neurotransmitter molecules from vesicles into the synaptic gap The postsynaptic neuron Has specialized receptor molecules which bind to the neurotransmitter and cause changes in the cell
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Postsynaptic Potentials Postsynaptic potentials are produced at synapses
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Postsynaptic Potentials When postsynaptic neuron receptors bind
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This note was uploaded on 04/07/2008 for the course BIO 101 taught by Professor Ward during the Fall '07 term at Shepherd.

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Nervous System - Chapter 38 Outline The Nervous system 38.1 What Are the Structures and Functions of Neurons p 762 38.2 How Is Neural Activity

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