Hart13 ppt ch04

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  • Image sources: Jim Wehtje/Getty Images (Image Ch04_01MRI) Scott Bodell/Getty Images (Image Ch04_04NervousSystemGraphic)
  • Image source: Brookhaven National Laboratory/Getty Images (Image Ch04_05BrainActivity); from top to bottom, the top and fourth PET scans are from a non-drug-user, the other PET scans are of a cocaine user
  • Figure 4.1 in text
  • Figure 4.2 in text
  • Figure 4.4 in text
  • Figure 4.5 from text
  • Figure 4.6 from text
  • Figure 4.7 from text
  • Figure 4.8 from text
  • Image source: Photodisc/Getty Images (Image Ch04_06YinYang)
  • Image source: National Cancer Institute Visuals Online, Dr. Giovanni Dichiro (Image Ch04_02PET)
  • Image source: Royalty-Free/Corbis (Image Ch04_03MRI)
  • Image source: Scott Bodell/Getty Images (Image Ch04_03NervousSystemGraphic)
  • Hart13 ppt ch04

    1. 1. Chapter 4 The Nervous System© 2011 McGraw-Hill Higher Education. All rights reserved.
    2. 2. Homeostasis  Humans must maintain their internal environment within certain limits  Temperature  Acidity  Water content  Sodium content  Glucose concentrations  Other physical and chemical factors© 2011 McGraw-Hill Higher Education. All rights reserved.
    3. 3. Components of the Nervous System  Nerve cells (neurons)  Analyze and transmit information  Over 100 billion neurons in system  Four defined regions  Cell body  Dendrites  Axon  Presynaptic terminals  Stimulation of receptors by psychoactive drugs can activate or inhibit a neuron© 2011 McGraw-Hill Higher Education. All rights reserved.
    4. 4. Neuron© 2011 McGraw-Hill Higher Education. All rights reserved.
    5. 5. Components of the Nervous System  Glial cells (Glia)  Provide firmness and structure to the brain  Get nutrients into the system  Eliminate waste  Form myelin  Create the blood-brain barrier  Communicate with other glia & neurons© 2011 McGraw-Hill Higher Education. All rights reserved.
    6. 6. Neurotransmission  Action potential = a brief electrical signal transmitted along the axon  Neurotransmitters are the “messengers”  Resting action potential is caused by uneven distribution of ions  Action potential occurs when sodium ions move across channels  Blocking channels prevents the action potential and disrupts communication between neurons© 2011 McGraw-Hill Higher Education. All rights reserved.
    7. 7. Action Potential© 2011 McGraw-Hill Higher Education. All rights reserved.
    8. 8. The Nervous Systems  Somatic nervous system  Sensory information  Voluntary actions  Autonomic nervous system (ANS)  Sympathetic branch  Parasympathetic branch  Central nervous system (CNS)  Brain  Spinal cord© 2011 McGraw-Hill Higher Education. All rights reserved.
    9. 9. Somatic Nervous System  Carries sensory information into the central nervous system  Carries motor (movement) information back out to the peripheral nerves  Controls voluntary actions  Acetylcholine is the neurotransmitter at neuromuscular junctions© 2011 McGraw-Hill Higher Education. All rights reserved.
    10. 10. Autonomic Nervous System  Monitors and controls the body’s internal environment and involuntary functions  Many psychoactive drugs affect the brain and the autonomic nervous system  Two branches often act in opposition  Sympathetic branch  “Fight or flight”  Parasympathetic branch© 2011 McGraw-Hill Higher Education. All rights reserved.
    11. 11. Central Nervous System  Consists of the brain and the spinal cord  Has many functions  Integration of information  Learning and memory  Coordination of activity© 2011 McGraw-Hill Higher Education. All rights reserved.
    12. 12. Chemical Pathways 1. Dopamine  Found in basal ganglia and other regions  Nigrostriatal dopamine pathway  Related to muscle rigidity  Mesolimbic dopamine pathway  Related to psychotic behavior  Possible component of the “reward” properties of drugs© 2011 McGraw-Hill Higher Education. All rights reserved.
    13. 13. Chemical Pathways 2. Acetylcholine  Found in the cerebral cortex & basal ganglia  Involved in Alzheimer’s disease, learning, memory storage 3. Norepinephrine  Regulates level of arousal and attentiveness  May play a role in initiation of food intake (appetite)© 2011 McGraw-Hill Higher Education. All rights reserved.
    14. 14. Chemical Pathways 4. Serotonin  Found in the brain stem raphe nuclei  May have a role in impulsivity, aggression, depression, control of food, and alcohol intake  Hallucinogenic drugs influence serotonin pathways 5. GABA (Gamma-amino butyric acid)  Found in most regions of the brain  Inhibitory neurotransmitter© 2011 McGraw-Hill Higher Education. All rights reserved.
    15. 15. Chemical Pathways 6. Glutamate  Found in most regions of the brain  Excitatory neurotransmitter 7. Endorphins  Opioid-like chemical occurring naturally in the brain  Play a role in pain relief, other functions© 2011 McGraw-Hill Higher Education. All rights reserved.
    16. 16. Common Neurotransmitters Neurotransmitter Type of effect CNS changes Drugs of abuse dopamine inhibitory- euphoria amphetamines, excitatory agitation cocaine paranoia GABA inhibitory sedation alcohol, relaxation Valium-type drowsiness barbiturates depression serotonin excitatory- sleep LSD inhibitory relaxation sedation acetylcholine excitatory- mild euphoria tobacco, inhibitory excitation nicotine insomnia endorphins inhibitory mild euphoria opioid block pain slow respiration© 2011 McGraw-Hill Higher Education. All rights reserved.
    17. 17. The Brain: Major Structures  Cerebral cortex  Basal ganglia  Hypothalamus  Limbic system  Midbrain, pons, and medulla  Brain stem© 2011 McGraw-Hill Higher Education. All rights reserved.
    18. 18. Cross-section of the brain: Major structures© 2011 McGraw-Hill Higher Education. All rights reserved.
    19. 19. Life Cycle of a Neurotransmitter 1. Neurotransmitter precursors are found circulating in the blood supply 2. Uptake: Selected precursors are taken up by cells, a process requiring energy 3. Synthesis: Precursors are changed (synthesized) into neurotransmitters through the action of enzymes 4. Storage: Neurotransmitters are stored in small vesicles© 2011 McGraw-Hill Higher Education. All rights reserved.
    20. 20. Life Cycle of a Neurotransmitter 5. When the action potential arrives, neurotransmitters are released into the synapse 6. Released neurotransmitters bind with receptors on the membrane of the next neuron 7. Neurotransmitters may have excitatory or inhibitory effects 8. Once a signal has been sent, neurotransmitters are removed from the synapse; may return or be metabolized© 2011 McGraw-Hill Higher Education. All rights reserved.
    21. 21. Neurons use enzymes to synthesize neurotransmitters© 2011 McGraw-Hill Higher Education. All rights reserved.
    22. 22. Schematic representation of the action of a synthetic enzyme. A precursor molecule and another chemical fragment both bind to the enzyme. The fragment has a tendency to connect with the precursor, but the connection is made much more likely because of the way the enzyme lines up to the two parts. After the connection is made, the new transmitter molecule separates from the enzyme.© 2011 McGraw-Hill Higher Education. All rights reserved.
    23. 23. Schematic representation of the release of neurotransmitter molecules from synaptic vesicles in the axon terminal of one neuron and the passage of those molecules across the synapse to receptors in the membrane of another neuron.© 2010 McGraw-Hill Higher Education. All rights reserved.
    24. 24. Schematic representation of the action of a metabolic enzyme. The transmitter molecule binds to the enzyme is such a way that the transmitter molecule is distorted and “pulled apart.” The fragments then separate from the enzyme.© 2011 McGraw-Hill Higher Education. All rights reserved.
    25. 25. Examples of Drug Actions  Alter neurotransmitter availability  Agonists  Mimic neurotransmitters  Antagonists  Occupy neurotransmitter and prevent its activation  Interference with reuptake© 2011 McGraw-Hill Higher Education. All rights reserved.
    26. 26. Chemical Theories of Behavior  Attempts to explain normal variations in behavior in terms of changes in brain chemistry  Greek physician Hippocrates and the four humors  Chinese philosophy—yin and yang© 2011 McGraw-Hill Higher Education. All rights reserved.
    27. 27. Chemical Theories of Behavior  No single biochemical theory of drug dependence has achieved sufficient experimental support  Monoamine theory of mood—too little activity in monoamine systems can cause depression, too much can cause mania© 2011 McGraw-Hill Higher Education. All rights reserved.
    28. 28. Brain Imaging Techniques: PET Scan© 2011 McGraw-Hill Higher Education. All rights reserved.
    29. 29. Brain Imaging Techniques: MRI Scan© 2011 McGraw-Hill Higher Education. All rights reserved.
    30. 30. Chapter 4 The Nervous System© 2011 McGraw-Hill Higher Education. All rights reserved.

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