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

2024
Views:

119

Pages:

4
Author:

Nick T.

Somatic Nervous System • nerve cells on the "front lines", interacting with the external environment • controls voluntary actions • Carries sensory information into the Central nervous System, or CAUS • Carries motor or movement information back out to the peripheral nerves • has the neurotransmitter acetyicholine at neuromuscular juncrions Autonomic Nervous System • monitors and controis the body's internal environment and involuntary funchons - ex: heart rate and blood pressure - many psychoactive drugs affect the brain and the autonomic nerrous Sysrem Simultaneously • to branches often act in opposition - Sympathetic branch ex: norepinephrine is involved in increasing heart rate " "Fight or tright" response - parasympathetic branch " ex: acetyichaine is involued in decreasing hlart rate. Chemical Pathways in the Brain • dopamine • mesolimbic dopamine pathway - from the ventral tegmental area in the midbrain to the nucleus accumbens. - proposed to medicte some types of payenotic behavior Reutes Nescarb and N grote ea - possible component of the "rewarding properties of drugs • nigrostriotal dopamine partway - From the substantia nigra to the Striatum, past tue hypothalamus - Substantial loss of cells lead to Parkinson's Disease • acetylonoline - pathways arise from cell bodies in the nucleas basalis in the lower part of the brain and project widely throughout the cerebral cortex - involved in Alzheimer's disease - acetylcholine blockers impair memory • norepineparine pathways - arise trom the locus ceruleus in the brain-stem and prosect bot up and down in the brain - influence the level of arousal and attentiveness - play a role in the initaten of food intake • Serotonin pathways - arise from the brainstem raphe nuclei and project bom upward into the brain and downward into the spinal cord - may have a rove in impulsiviry and aggression, depression, food intone and weight Control, and alcond use • Serotonin receptors play a role in the actions of some hallucinogenic drugs • GABA or Cramma-Amino Butyric Acid - not neatly organized into discrete pathways - found in most regions of the CNS = inhibitory neurotransmiter, which exerts generaited inhibitory functions • Glutamate - Found in most regions of the brain - excitatory neurotransmitter - evidence indicates that Specific glutamate parmways may be important for the expression of some psychoactive drug effects • endorphins - found throughout the brain - naturally occurring morphine-like chemicals - play a role in pain reief and other funcions Figure 4.5: Cross Section of the Brain: Major Structures Life Cycle of a Neurotransmitter • Step l: neurotransmitter precursors are found Circulating in the blood supply • Step 2: uptake - Selected precursors are taken up by cells • Step 3: synthesis - precursors are Synesized into neurotransmitters through the actons of enzymes * Step 4: Storage - neurotransmitters are stored in Synaptic vesicles near the terminal from which they will be released • Step 5: revease - when the action potental arrives, neurotransmitters are releosed into the Synapse.