Unformatted text preview: Chapter 3 Chapter How Drugs Work in the How Body and on the Mind Body ROUTES OF DRUG ROUTES OF DRUG ADMINISTRATION Oral administration (by mouth) Injection (intravenous, intramuscular, or subcutaneous injection) Inhalation (smoking) Absorption through the skin or membranes (intranasal sniffing, sublingual absorption, rectal suppository, transdermal patch) ELIMINATION HALFLIFE ELIMINATION HALFLIFE A drug’s elimination halflife refers to the length of time it takes for the drug to be reduced to 50 percent of its equilibrium level in the bloodstream. Elimination halflife of nicotine — a few hours cocaine — a few hours marijuana — much longer FORMS OF DRUG INTERACTION FORMS OF DRUG INTERACTION (2 or more drugs taken together)
ACUTE INTERACTIONS Additive interaction Hyperadditive (synergistic) interaction Potentiation (a special kind of synergism) Antagonistic interaction CHRONIC INTERACTIONS Crosstolerance Crossdependence INDIVIDUAL DIFFERENCES INDIVIDUAL DIFFERENCES Weight Gender Ethnicity NERVOUS SYSTEM ORGANIZATION NERVOUS SYSTEM ORGANIZATION
Central nervous system (CNS) • Spinal cord • Brain Peripheral nervous system • • Somatic system – CNS connects to VOLUNTARY actions Autonomic system – CNS connects to INVOLUNTARY actions Sympathetic branch – fight/flight Parasympathetic branch – restores NRG STIMULANTS AND DEPRESSANTS STIMULANTS AND DEPRESSANTS Stimulant drugs usually stimulate sympathetic autonomic responses, inhibit parasympathetic autonomic responses, or both. Depressant drugs usually stimulate parasympathetic autonomic responses, inhibit sympathetic autonomic responses, or both. MAJOR SECTIONS OF THE BRAIN MAJOR SECTIONS OF THE BRAIN
• HINDBRAIN: medulla, pons, cerebellum substantia nigra • MIDBRAIN: • FOREBRAIN: hypothalamus, thalamus, cerebral cortex BASIC ELEMENTS OF NEURONS BASIC ELEMENTS OF NEURONS Cell body — comprising the bulk of the neuron and containing the nucleus Dendrites — relatively short appendages that receive information from the outside (the environment or other neurons) Axon — relatively long appendage that transmits information outward to muscles or other neurons SIX MAJOR SIX MAJOR NEUROTRANSMITTERS Acetylcholine Norepinephrine Dopamine Serotonin Gamma aminobutyric acid (GABA) Endorphins EXCITATION AND EXCITATION AND INHIBITION When a neuron is excited, it emits a greater number of nerve impulses per second. When a neuron is inhibited, it emits a lesser number of nerve impulses per second. Lifecycle of neurotransmitter SIX MAJOR SIX MAJOR NEUROTRANSMITTERS Acetylcholine Norepinephrine Dopamine Serotonin Gamma aminobutyric acid (GABA) Endorphins THE BLOODBRAIN BARRIER THE BLOODBRAIN BARRIER The bloodbrain barrier is a system whereby some substances in the bloodstream are excluded from entering the nervous system. Fat solubility is a key factor in the ability of a drug to pass the bloodbrain barrier. DOUBLEBLIND PLACEBO DOUBLEBLIND PLACEBO CONTROL DESIGN Individuals administering the drug do not know whether the substance administered is actually the drug or a placebo. Individuals receiving the drug do not know whether the substance received is actually the drug or a placebo. Placebo Effect – very interesting phenomenon! Cocaine in the Brain Cocaine in the Brain ...
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- Fall '08
- Neurotransmitter, parasympathetic autonomic responses, sympathetic autonomic responses