Drugs and Society
Drugs and Society BIO 1033
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This 5 page Class Notes was uploaded by Mr. Uriel Harvey on Thursday October 29, 2015. The Class Notes belongs to BIO 1033 at University of Texas at San Antonio taught by Deborah Armstrong in Fall. Since its upload, it has received 11 views. For similar materials see /class/231358/bio-1033-university-of-texas-at-san-antonio in Biology at University of Texas at San Antonio.
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Date Created: 10/29/15
C HAPTE R 2 I How drugs get to the brain A Five routes ofadministration 1 Inhaling vaporized drug is absorbed into the blood Via capillaries oflung air sacs onset in 710 sec Fastest 2 Injecting the drug is put directly into the body with a needle Intravenous onset in 1530 sec intramuscular onset in 35 min subcutaneous 35 min 3 Snorting and mucosal exposure drugs like cocaine and heroin are absorbed by blood vessels in the nose or mouth 35 min 4 Orally Drugs are absorbed into the blood via capillaries lining the small intestine 2030 min 5 Contact Liquid LSD into the eye 35 min skin patches such as those containing nicotine release set quantities for up to 7 days onset in 12 days Slowest B Drug circulation 1 Once a drug is absorbed into the bloodstream it circulates throughout the body 1 2 The time it takes a drug to reach the brain depends on blood volume adult or child the number of blood vessels saturating various organs and the speci c characteristics of the drug itself 2 Liver 3 The drug itself C The bloodbrain barrier Not over the counter drugs 1 The capillaries which supply blood to the brain have a fatty protective covering to prevent toxins Viruses and bacteria from entering the central nervous system CNS This protective layer is called the bloodbrain barrier 2 Psychoactive drugs can cross the bloodbrain barrier because they are fat soluble The more fat soluble they are the faster they enter the brain and the more intense the reaction Example heroin is more fat soluble than morphine Morphine Heroin Diacetyl morphine II The Nervous System A The nervous system is the principal target of psychoactive drugs It is a network of 100 billion nerve cells with 100 trillion connections 1 It is divided into two major parts the peripheral nervous system and the central nervous system a The peripheral nervous system is further subdivided into two parts i The autonomic nervous system which controls involuntary functions ie breathing blood pressure The somatic nervous system which transmits signals from our senses into the brain and transmits motor commands out to our muscles Carries senses from our brain to move our muscles b The central nervous system brain and spinal cord which receives analyzes and transmits messages to various systems as well as enabling us to reason 2 Many psychoactive drugs affect the reward pleasure system of the brain which contains structures such as the nucleus acculnbens and hypothalamus Axon f release neurotransmitte Dendrites Axon terminals Cell Body III Nerve cells or neurons the building blocks of the nervous system have four parts dendrites which contain chemical receptors the cell body the axon and the terminals A Nerve cells conduct electrical impulses and communicate with each other by releasing tiny amounts of chemicals called neurotransmitters Dendrites Examples of neurotransmitters acetylcholine dopamine norepinephrine serotonin endorphins substance P GABA B Neurotransmitters are released into synapses which are microscopic gaps between neurons Axon Dendrites gt Axon Termlnal C Psychoactive drugs work because they bind to existing receptor sites on neurons and either mimic or block the normal functions of neurotransmitters Physiological Responses to Drugs A ToleranceAfter repeated exposure to a drug the body begins to adapt to its presence you need bigger dose 1 Dispositional tolerance the liver speeds up the disposal metabolism of the drug 2 Phar39macodynamic tolerance nerve cells become less sensitive to the drug by producing fewer receptors 3 Behavioral tolerance the person learns to compensate for the affects of intoxication 4 Reverse tolerance increasing sensitivity as tissues degenerate alcoholism 5 Acute tolerance almost instantaneous tolerance Sudden Onset 6 Select tolerance a person becomes tolerant to mood changes produced by a drug but not to other physical effects of that drug overdose B Tissue dependence tissues and organs come to depend on a drugjust to function normally C Withdrawal When a user stops taking their drug of addiction the body39s chemistry tries to restore its original chemical balance and undesired side effects called withdrawal symptoms occur The three types of withdrawal are CRAVING real symptoms 1 Nonpurposive withdrawal actual physical symptoms that occur when drug use ceases sweating goose bumps diarrhea tremors 2 Purposive withdrawal faked withdrawal symptoms or psychosomatic withdrawal symptoms neurotic delayed 3 Protracted withdrawal recurrence of Withdrawal symptoms after a person has already detoxi ed often causing craving for a drug often resulting in relapse Opiates Heroin Morphine Hydrocodone Vicodin Effects Withdrawal Constipation Diarrhea Drowsiness relaxed calm anxious shaking Heart rate down heart rate up D Metabolism the process of processing and eliminating foreign substances from the body 1 A drug is broken down into metabolites neutralized principally by the liver 2 Drug metabolites are eliminated principally by the kidneys in addition to the lungs sweat andor feces 3 Other factors affecting metabolic rates a Age e Health b Race f Emotional State c Heredity g Other drugs d Sex V Desired effects vs side effects A People take drugs for confidence energy pain relief anxiety control social con dence relief of boredom altered consciousness escape or to gain a competitive edge B The problem is that drugs also cause unwanted side effects ranging from the uncomfortable to the lifethreatening VI Levels of use A Level of use is judged rst by the amount frequency and duration of use then by the effect use has on the individuals life The six levels of use are 1 Abstinence 2 Experimentation 3 Socialrecreational 4 Habituation 5 Abuse Drug abuse is defined as the continued use of the drug despite negative consequences 6 Addiction Person spends most of their time either using getting or thinking about the drug Often they deny there is a problem and claim they can stop anytime they want VI Theories of addiction A Addictive Disease Model Addiction is a chronic progressive relapsing incurable and potentially fatal condition that is mostly a consequence of genetic irregularities B Behavioralenvironmental model In uences of one39s environment including stress abuse anger and peer pressure can induce addiction C Academic Model It is the use of drugs that causes the body to adapt through physiological mechanisms such as tolerance tissue dependence Withdrawal and psychological dependence VII Heredity Enviromnent and Psychoactive Drugs A Heredity 1 Some individuals may be genetically susceptible to addiction 2 Presence of alcoholic family members increases susceptibility to alcoholism 1 alcoholic parent 34 chance of being an alcoholic 3 Increased susceptibility means that if a person drinks heshe becomes a compulsive drinker quicker a more intense reaction to the first drink greater tolerance B Environment Stress physical or mental abuse companions who use the drug social acceptance of drug use medical problems etc all determine drug use habits C Psychoactive drugs The habitforming nature of the drug itself and how it is administered contributes to the probability of addiction The drugs that push the hardest and quickest toward addiction are in order from fastest to slowest Smoking tobacco
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