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Neural Communication

Neural Communication. Will Explain Why We FEEL……. Nervous. Strong. Sick. Pain. It all Starts with the Neuron 42-44. What are neurons?. Nerve cells (smallest unit of Nervous System) Billions/Cells do not regenerate but can adapt Conduct impulses that carry signals Types Sensory

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Neural Communication

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  1. Neural Communication

  2. Will Explain Why We FEEL…… Nervous Strong Sick Pain

  3. It all Starts with the Neuron 42-44

  4. What are neurons? • Nerve cells (smallest unit of Nervous System) • Billions/Cells do not regenerate but can adapt • Conduct impulses that carry signals • Types • Sensory • Respond to incoming stimuli • Transmit information from senses to brain • Motor • Relay information from the brain to rest of the body • Interneurons • Process information between sensory and motor

  5. What are the parts of a neuron? • Cell Body • Life support center • Dendrites • Receive messages from other cells (INPUT) • Axons • Passes messages away from the cell body to other neurons (OUTPUT) • Myelin Sheath • covers the axons and helps speed neural impulses • Terminal Branches • Ends of axons; contain neurotransmitters • Synaptic Gap • Space between terminal branches and dendrites

  6. Neuron: Internally: message electrical. Externally: message chemical

  7. How are messages sent? Neurons do NOT touch each other – space b/w = synapse

  8. How are messages sent? • Neuron fires (action potential) through the synapses b/w neurons • In the form of a neurotransmitter • Process is electrochemical

  9. The All-or None Response • The idea that either the neuron fires or it doesn’t- no part way firing. • Like a gun

  10. Steps of Action Potential • Electrically charged atoms that stimulate neuron = ions • Interior of resting neuron = negative ions • Exterior of resting neuron = positive ions • Start of action potential comes from depolarization = positive ions let in

  11. Steps of an Action Potential • Ions enter the receiving neuron = exciting or inhibiting • Excitatory signals = pushing neuron’s accelerator • Inhibitory signals = pushing neuron’s brake • Threshold = Excitatory minus Inhibitory signals. If more excitatory, neuron will “fire” • toilet flush analogy

  12. How are messages sent? Refresh • Depolarization • Semipermeable cell membrane lets positively charged ions in. • Action Potential • If excitatory signals minus inhibitory signals exceed threshold • “all-or-none” response: neurons either fire or don’t • Release of Neurotransmitter • Cross synaptic gap and bind to receptors on receiving neuron • Refractory Period • Positively charged ions are pumped back outside; then neuron can fire again.

  13. TRANSITION SLIDE

  14. How do neurotransmitters influence us? P. 44-47 Chemical messengers released by terminal buttons through the synapse (over 60, you need to know 4). • Particular neurotransmitters have particular effects on behavior and emotions • Particular brain pathways use particular neurotransmitters • Examples: • Acetylcholine and memory • Dopamine and mobility • Serotonin and depression • Endorphins and pain

  15. Acetylcholine & Memory • Its function is motor movement and memory. • Lack of is linked to Alzheimer’s • When it’s released, muscles contract Botulin blocks transmission of Ach = paralysis

  16. Dopamine & mobility • Its function is motor movement and alertness. Lack of dopamine (death of nerve cells) is associated with Parkinson’s disease. Overabundance is associated with schizophrenia.

  17. Serotonin & depression • Function deals with mood control. Lack of serotonin has been linked to depression.

  18. Endorphins & Pain • Function - deals with pain control. • Natural opiates “runners high” • Response to pain & vigorous exercise We become addicted to endorphin causing feelings.

  19. How do drugs influence neurotransmitters? • 1. Block reuptake • … of neurotransmitter at pre-synaptic neuron  overabundance 0f neurotransmitter • Examples: Prozac = serotonin, cocaine = dopamine • 2. Mimic neurotransmitters- similar enough to occupy receptor site • Called agonists • morphine mimics endorphins • THC (in marijuana) & nicotine mimic dopamine • 3. Block receptor site – not similar enough to stimulate the receptor • Called Antagonist • Prevent neurotransmitter message from being relayed • Example: curare poison, Ach (no muscle contraction) • Essentially stop producing own natural opiates/endorphins • Always need a fix, dependency, more, unpleasant feelings

  20. Agonists and Antagonists

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