Chapter 3 _ Neuropsychology - Chapter 3 Neuroscience And...

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Chapter 3 Neuroscience And Behavior Parts of a Neuron Neuron: cells in the nervous system that communicate with one another to perform information-processing tasks (approx. 100 billion neurons in the brain). cell body : coordinates information-processing tasks and keeps the cell alive. dendrites : receives information from other neurons and relays it to the cell body. axon : transmits information to other neurons, muscles, or glands. myelin sheath : insulating layer of fatty material. nodes of Ranvier synapse : the junction or region between the axon of one neuron and the dendrites or cell body of another. Types of Neurons and Cells Glial cells : support cells found in the nervous system. Sensory neurons : neurons that receive information from the external world and convey this information to the brain via the spinal cord. Motor neurons : neurons that carry signals from the spinal cord to the muscles to induce movement. Interneurons : neurons that connect sensory neurons, motor neurons, or other interneurons. Electric Signaling: Communicating Information Within a Neuron The communication of information within and between neurons proceeds in two stages: conduction of an electric signal within a neuron from dendrite to cell body and axon. transmission of electric signals between neurons over the synapse. Ions : small electrically charged molecules that flow in and out of the cell. Electric Signaling: Communicating Information Within a Neuron Resting potential : the difference in electric charge between the inside and outside of a neuron’s cell membrane. When the neuron is at rest, positively charged potassium ions (K+) flow out. Cell is negatively charged (-70 millivolts). Action potential : an electric signal that is conducted along an axon to a synapse. Occurs only when threshold for stimulation is reached; all-or-none . During action potential, positively charged sodium ions (Na+) flow in. Cell is positively charged (+40 millivolts). Refractory period : the time following an action potential during which a new action potential cannot be initiated. Chemical Signaling: Synaptic Transmission Between Neurons An action potential reaches the end of an axon at the terminal button and a neurotransmitter is released into the synapse, collected at the receptor of the receiving neuron. terminal buttons : knoblike structures that branch out from an axon. neurotransmitters : chemicals that transmit information across the synapse to a receiving neuron’s dendrites. receptors : parts of the cell membrane that receive the neurotransmitter and initiate a new electric signal. postsynaptic neuron : the receiving neuron. presynaptic neuron : the sending neuron. Chemical Signaling: Synaptic Transmission Between Neurons
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Neurotransmitters leave the synapse. Reuptake
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This note was uploaded on 03/27/2012 for the course PSYC 2305 taught by Professor Steven during the Spring '10 term at Texas A&M University, Corpus Christi.

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Chapter 3 _ Neuropsychology - Chapter 3 Neuroscience And...

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