HSCI 1130 Lecture Notes - Lecture 4: Neuroglia, Primary Cell, Water Content
16 Mar 2019
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Document Summary
Humans must maintain their internal environment within certain limits. Nervous system is composed of two primary cell types. Glial cells or glia (10-50x as many glia as neurons) Stimulation of receptors by psychoactive drugs can activate or inhibit a neuron. Each of these defined regions contribute to the neurons ability to communicate with other neurons, and psychoactive drugs exert effects within each of these regions. Action potential a brief electrical signal transmitted along the axon. Resting action potential is caused by uneven distribution of ions. Action potential occurs when sodium ions move across channels. Blocking channels prevents the action potential and disrupts communication between neurons (numbing cream) Depolarization: overshoot phase, action potential is reached , very positive. Hyperpolarization: undershoot phase, returning to homeostasis initially very negative. Carries sensory information into the central nervous system. Carries motor (movement) information back out to the peripheral nerves. Monitors and controls the body internal environment and involuntary functions.
