Psychology Chapter 3 Notes

Psychology Chapter 3 Notes - Psychology Chapter 3...

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Psychology Chapter 3 – Biological Processes Organization of Nervous System 1. The brain has 100 billion neurons Three Components of Neurons 1. Soma – Cell Body 2. Dendrites – Receives neural impulses from other neurons 3. Axon – Carries nerve impulses away from the neuron 4. Sensory Neurons – Make the initial contact with the environment and are responsible for carrying the message inward toward the spinal cord and brain. 5. Interneurons – The most plentiful type of neurons, make no direct contact with the world but they convey information from one internal processing site to another. 6. Motor Neurons – Carry the message and commands away from the central nervous system to the muscles and glands that directly produce the behavioral response. Terminal Button and Synapse 1. Terminal Button – Bulge or swelling at the end of each axon fiber. Contains neurotransmitter chemicals. 2. Synapse – Gap between the terminal button of one neuron and dendrites of another. Neuron Structure ** Dendrite > Soma (Cell Body) > Axon > Terminal Buttons
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Nerve Impulse: Resting Potential 1. All neurons have electrical charge when they are not receiving or transmitting nerve impulses. 2. The resting potential is the electrical charge that exists between the inside and outside of the cell membrane. This is created by electrically charged ions that are unevenly distributed across the cell membrane. 3. There are more – Charged chloride ions and protein molecules inside the cell, and more + charged sodium and potassium ions outside the cell. 4. The fluid inside the cell is negative in comparison to the fluid outside the cell. – 70mV is typical. Nerve Impulse: Action Potential 1. Action Potential is the all-or-nothing electrical signal that travels down the axon. 2. Depolarization occurs if neuron receives excitatory stimulation. + Sodium ions begin to flow into the cell via expanded pores. 3. Increase of + sodium ions moves electrical change from –70mV toward 0 mV. Chances increase that neuron will fire. 4. Inhibitory stimulation leads to hyperpolarization. Electrical potential becomes more negative and neuron is less likely to fire. Nerve Impulse 1. Travels the length of impulse in all-or-nothing fashion. The “strength” does not diminish as the impulse travels. 2.
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This note was uploaded on 04/26/2008 for the course PSYC 101 taught by Professor Black during the Fall '03 term at Auburn University.

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Psychology Chapter 3 Notes - Psychology Chapter 3...

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