University:
York University
Course:
AP/SOSC 3118 | Drugs And Society
Academic year:

2024
Views:

209

Pages:

3
Author:

Nick T.

The Nervous System Homeostasis humans maintain their internal environment within certain limits ex: body temperature, water content, and glucose concentrations psychoactive drugs influence homeostasis -alcohol inhibits the release of antidiuretic hormone vasopressin Causes an increase in the excretion of urine Compared with light drinkers, heavy drinkers produce less urine after a drink - during alconol withdrawal, heavy drinkers exhibit an increased vasopressin release Positive and Negative Feedback • feedback loop: biological occurrence wherein the output of a system amplifies (positive feedback) or innibits (negative feedback) a System • Feedback loops help to maintain homeostasis Negative Feedback: Positive Feedback: Childbirth Components of the Nervous System • two major types of cells in the nervous system - neurons or nerve cells gila or glial cells Neurons primary elements of the nervous system that analyze and transmit information • four defined regions cell body Contains the processes that maintain the life of the neuron, including the nucleus - dendrite Figure -4.3: Every Neuron Has Four Regions: Cell Body, Dendrites, Aren, and Axon Terminals Contains receptors that respond to Chemical Signals axon specializes in transmitting signals to other neurons axon terminal Contains Synaptic vesicles that Store neurotransmitters Gila • major functions providing firmness and Structure to the brain getting nutrients into the System - eliminating waste Forming myelin Communicating with other glia and neurons Creating the blood-brain-barrier a drug molecule must be able to pass the barrier to be psychoactive Protecting the brain from toxic chemicals Neurotransmission transferring information from one neuron to another at a synapse • brief chain of events resting potential is caused by an uneven distribution of ions, resulting in the hyperpolarization of a neuron ion Channels open, which allows ions to move inside the cell depolarized the cell making if the cell is depolarized to the threshold of excitation, "all-or-none" action potential occurs * action potential is a brief electrical signal transmited along the axon when a neuron fires note: blocking ion channels prevents the action potential and disrupts neuronal Communication Do dit Double-click to Central Nervous System • Consists of the brain and spinal cord • Functions - integration of information - learning and memory - Coordination of activity