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How Drugs Enter The Body (1)

How Drugs Enter The Body (1). Oral Administration - substance is ingested through the mouth - digested and absorbed in gastrointestinal tract - passes through liver - carried to the brain through the circulatory system.

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How Drugs Enter The Body (1)

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  1. How Drugs Enter The Body (1) • Oral Administration - substance is ingested through the mouth - digested and absorbed in gastrointestinal tract - passes through liver - carried to the brain through the circulatory system. • -Most absorption occurs in 5 to 30 minutes, but is not completed for up to 6 to 8 hours • -Slowest method

  2. How Drugs Enter The Body (2) • Injection - bypasses the digestive tract. • Intravenous -injected directly into a vein drug arrives in the brain within 15 seconds; effect are irreversible • Intramuscular - injected into a large muscle group, slower absorption • Subcutaneous - injected under under the skin, slowest absorption

  3. How Drugs Enter The Body (3) • Inhalation - smoke or vapors of a substance are drawn into the lungs. • - Simplest way to receive a drug • - Passes from alveoli in the lungs to blood stream and then to the brain • - Fastest pathway for a drug to enter the body • - Risk permanent damage to lungs

  4. How Drugs Enter The Body (4) • Absorption Through Membranes • Intranasal-absorption through mucous membranes in the nose • Sublingual - absorption occurs under the tongue • Transdermal - absorption occurs through the skin

  5. How Drugs Leave The Body • All substance are excreted through urination or defecation. • Water Soluble substances pass through the body more quickly. • Factors Effecting the Process of Biodegradation • - Quantity - larger the amount, more quickly metabolized (except for alcohol) • - Type of drug

  6. Timing • Timing effects the physiological impact of a substance. • Latency Period - The amount of time from ingesting a substance till you begin to feel its effect. • The larger amount of a substance in blood stream the stronger the effects. • An individual can reach the maximum positive effect dose but their level still continue rise resulting negative side effects.

  7. Drug Interactions • Additive - Occurs when two or more drugs combine to produce an effect greater than effect of either drug taken alone. • Additive: 1 + 1 = 2 • Synergistic (hyperadditive): 1 + 1=6 • Potentiation - a drug with no effect is combined with another drug to cause a toxic effect. • Antagonistic - one drug weakens or cancels out the effect of another drug.

  8. Homeostasis • Maintenance of internal stability of the body. • Body continually adjusts and adapts to internal and external changes in the environment. • Self-Regulating Mechanisms • Organ function • Temperature, blood pressure • Metabolism

  9. Homeostasis • Two Major body systems • Nervous System • Regulated by the release of neurotransmitters • Responsible for sending chemical messages • Endrocine System • Regulated by release of hormones • Functioning of many vital organs

  10. Nervous System (1) • Central Nervous System • Brain and spinal cord • Central mass of nerve tissue • Integrates information, learning, memory, coordination

  11. Nervous System (2) • Somatic Nervous System • Sensory nerves - information to CNS • Motor nerves - impulses to muscles • Autonomic Nervous System • Regulates body functions • Involuntary functions

  12. Neurons • Specialized nerve cells • Receive and send information • Parts of neurons • Cell body: nucleus, dendrites with receptors • Axon: long wire like extensions • Synapse: space between neurons

  13. How CNS Works (1) • Neurotransmitters: signaling chemicals released by neurons • Have brief localized effects • Enables communication between neurons • Released into synapse (1/10,000 inch) • Receptors: specialized to receive chemical signals

  14. How CNS Works (2) • Neurotransmitter and receptor are like “lock and key” • Response is specific depending on which receptor is activated • Receptor will either “excite” or “inhibit” electrical impulse.

  15. Neurotransmitters (1) • Enable brain to receive, process, and respond to information by carrying impulse from one neuron to the next. • Dopamine - mild euphoria, excitation, insomnia • Endorphins - euphoria, blocks pain, slows respiration

  16. Neurotransmitters (1) • Gamma-aminobutyric acid (GABA) • sedation, relaxation, drowsiness, depression • Acetycholine - mild euphoria, excitation, insomnia • Serotonin - sleep, relaxation, sedation

  17. How Drugs Work (1) • Drugs enter the body; carried through the circulatory system to cells • Molecular structure is similar to neurotransmitters • Cross the blood brain barrier

  18. How Drugs Work (2) • Drug actions • May act on synthesis, storage, release, re-uptake, or metabolism of transmitter • Alter the availability of neurotransmitter • Mimic action of a neurotransmitter and activate or occupy receptor to prevent neurotransmitter from activating it.

  19. Specific Actions of Drugs • Dopamine: activated by stimulants • Serotonin: activated by LSD • GABA: activated by alcohol and other depressants • Endorphins: activated by narcotics

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