Psych Review Ch3

Psych Review Ch3 - Chapter 3: The Biological Bases of...

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Chapter 3: The Biological Bases of Behavior 1. Describe the various parts of the neuron and their functions. Neurons are individual cells in the nervous system that receive, integrate, and transmit information. The soma, or cell body, contains the cell nucleus and much of the chemical machinery common to most cells. Dendrites are the parts of a neuron that are specialized to receive information. The axon is a long, thin fiber that transmits signals away from the soma to other neurons or to muscles or glands. The myelin sheath is insulating material that encases some axons. Terminal buttons are small knobs that secrete chemicals called neurotransmitters. A synapse is a junction where information is transmitted from one neuron to another. 2. Describe the main functions of glial cells. Glial cells are found throughout the nervous system, and they provide various types of support for the neurons. Some types of glial cells can detect neural impulses and send signals to other glial cells, as well as provide nurturing support. Although glial may contribute to information processing in the nervous system, the bulk of this crucial work is handled by the neurons. 3. Describe the neural impulse. A neuron is like a battery. The resting potential of a neuron is its stable, negative charge when the cell is inactive. An action potential is a very brief shift in a neuron’s electrical charge that travels along an axon. The absolute refractory period is the minimum length of time after an action potential during which another action potential cannot begin. Either a neuron fires or it doesn’t. Stronger stimulus cause neurons to fire more rapidly. 4. Explain how neurons communicate at chemical synapses. Two neurons are separated by a synaptic cleft, a microscopic gap between the terminal button on one neuron and the cell membrane of another neuron. The presynaptic neuron fires the signal and the postsynaptic neuron receives it. Neurotransmitters are chemicals that transmit information from one neuron to another. Chemicals are stored in small sacs called synaptic vesicles. 5. Describe the two types of postsynaptic potentials and how neurons integrate signals and form neural circuits. A postsynaptic potential is a voltage change at a receptor site on a postsynaptic cell membrane. An excitatory PSP is a positive voltage shift that increases the likelihood that the postsynaptic neuron will fire action potentials. An inhibitory PSP is a negative voltage shift that decreases the likelihood that the postsynaptic neuron will fire action potentials. Reuptake is the process in which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane. Perceptions, thoughts, and actions depend on patterns of synaptic firings, and ironically, the elimination of old synapses appears to play a larger role in the sculpting of neural networks than the creation of new synapses. Synaptic pruning is a key process in the formation of neural networks that are crucial to
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This note was uploaded on 04/29/2008 for the course PSYCH 201 taught by Professor Raymark during the Spring '08 term at Clemson.

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Psych Review Ch3 - Chapter 3: The Biological Bases of...

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