PSY100H1 Lecture Notes - Lecture 5: Parasympathetic Nervous System, Sympathetic Nervous System, Somatic Nervous System

• School: UTSG
• Department: Psychology
• Course: PSY100H1
• Professor: Ashley Waggoner Denton

Document Summary

The nervous system is the body"s electrochemical communication circuitry. Parasympathetic nervous system -> digestion of food etc. Increase the likelihood that the neuron will fire. Decrease the likelihood that he neuron will fire. They do this by affecting the polarization of the cell. Neurons fire if the excitatory input reaches a certain threshold. A neuron fires with the same potency each time. The neural impulse that passes along the axon and subsequently causes the release of chemicals from the terminal buttons. If the neuron reaches its excitatory threshold, it will fully depolarize. Na+ channels open and the charge across the membrane reverses. Becomes more positive inside the cell, due to influx of na+ At the peak of the action potential, na+ channels will close and k+ channels actually lead temporary hyperpolarization. During which the cell cannot fire (refractory period) K+ channels close, and the cells return to its (polarized) resting state.