PNS: Anatomy of the Sympathetic Division∙Originates from T1through L2▪Ganglia are at the sympathetic trunk (near the spinal cord)▪Short pre-ganglionic neuron and long post-ganglionic neuron transmit impulse from CNS to theeffector▪Norepinephrine and epinephrine are neurotransmitters to the effector organsPNS: Anatomy of the Parasympathetic Division▪Originates from the brain stem and S1through S4▪Terminal ganglia are at the effector organs▪Always uses acetylcholine as a neurotransmitterPNS: Autonomic Functioning▪Sympathetic—―fight or flight‖▪Response to unusual stimulus▪Takes over to increase activities▪Remember as the ―E‖ division▪Exercise, excitement, emergency, and embarrassment▪Parasympathetic—―housekeeping‖ activites▪Conserves energy▪Maintains daily necessary body functions▪Remember as the ―D‖ division▪digestion, defecation, and diuresisEFFECTS OF THE SYMPATHETIC AND PARASYMPATHETIC DIVISIONS OF THE ANS
DEVELOPMENT ASPECTS OF THE NERVOUS SYSTEM▪The nervous system is formed during the first month of embryonicdevelopment▪Any maternal infection can have extremely harmfuleffects▪The hypothalamus is one of the last areas of the brain to develop▪No more neurons are formed after birth, but growth and maturation continues forseveral years▪The brain reaches maximum weight as a young adultDRUGS AND THE NERVOUS SYSTEMDrug–any substance, other than food that changes the structure or functionof the body▪Legal▪Illegal1. Stimulants▪Increase -Heart rate, Blood pressure,Breathing▪Release of neurotransmitters at some synapses in the brain▪Deplete neurotransmitters and lead to:▪Fatigue Circulatory problems▪Hallucinations Depression2. Depressants▪Dec rease -Heart rate, Breathing rate, Blood pressure,▪Relax muscles▪Relieve tension▪Enhances release of neurotransmitters that prevent nerves cells from firing▪Alcohol with depressants can lead to death–depresses CNS to a point one stopsbreathing 3. Opiates▪Mimics endorphins▪Endorphin–natural chemical in brain that helps overcome pain▪When person stops taking▪Brain has adjusted to high levels of endorphins▪Cannot produce enough natural endorphins▪Suffer uncontrollable pain and sickness
4. Cocaine▪Sudden release ofDopamine▪Powerful Stimulant▪Increases heart rate and blood pressure▪First time users can have heart attack▪Dopamine–neurotransmitter in brain that is released to give feeling of pleasure andsatisfaction 5. Marijuana▪Active ingredient (THC) tetrahydrocannabinol▪More destructive to lungs than cigarettes▪5 marijuana cigs = 120 conventional cigs▪Results in:▪Lower WBC count by 40% - susceptible to infections▪Teens–▪inhibits maturity▪Retards normal brain growth▪Memory loss▪Inability to concentrate▪Fall short on memory as well as math and verbal skills▪Males–reduced testosterone levels and increases estrogen levels▪Females–▪disturbs menstrual cycle▪DNA damage to eggs▪More Effects (FYI)▪Impaired perception▪Loss of coordination▪Increased risk of accidents▪Impaired judgement▪Loss of motivation▪Diminished inhibitions▪Increased heart rate▪Anxiety, panic attacks, and paranoia▪Hallucinations▪Damage to the respiratory, reproductive, and immune systems▪Increased risk of CANCER▪Psychological dependency6. Alcohol▪Depressant▪Slows down CNS▪40% of 50,000 highway deaths are caused by drinking and driving
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