Test 1 Lecture 5

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Test 1 Lecture 5
2012-04-25 23:04:58
Test Lecture

Test 1 Lecture 5
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  1. What are some graded potential examples?
    • 1. post-synaptic
    • 2. receptor
    • 3. end plate (somatic end of the motor neuron
    • 4. pace-maker potential
  2. Graded potentials
    • 1. Magnitude depends on stimulus strength
    • 2. current spread is decremental over distance
    • 3. No threshold, can be summated (temporally and spatially)
    • 4. No refractory period
  3. Compound Action potential
    • recorded from a nerve which is a collection of neurons
    • The more axons that are stimulated, the higher the action potential reading is
  4. Draw a compound action potential and demonstrate the effect increasing the distance between R1 and R2 have
    Find answer
  5. How do the sodium channels win?
    • Because not only is there a concentration gradient there is also a chemical gradient that pulls sodium into the cell;
    • Potassium only has the concentration gradient
  6. T/F: Muscarinic cholingeric receptors are ion channels. Why or why not?
    False. it is a membrane protein that does not serve as an ion channel, one protein subunit that is not active
  7. Muscarinic Cholinergic Receptors
    1. In intestinal smooth muscles, how do alpha subunit diffusion help to reach threshold easier?
    2. In heart muscle, how do the beta-gamma subunit diffuse through and cause you to be further away from threshold?
    • 1. By decreasing potassium permeability, which hypopolarizes the membrane.
    • 2. The beta-gamma subunit diffuses through and increases the potassium permeability which hyperpolarizes the cell causing you to be further away.
  8. What drug inhibits the effects of Ach? And how?
    Curare is a competitive inhibitor, causing Ach nicotinic recpetors to be blocked, causing paralysis, but pain still persists
  9. What drug blocks muscarinic cholinergic receptors?
    Atropine. come from Belladonna, and basically gives the target cell the effect what normally a nicotinic receptor would. ex. dilate pupil...