Physiology 4

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Physiology 4
2011-01-17 15:29:00
Physiology shoreline moffat

Lecture 4 with moffat at shoreline
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  1. Action potential steps
    • 1. Resting: the All Na and K channels are closed mince leaky gates of -70
    • 2. depolorizing phase: the Na channels open but the K gates are still closed. getting positive
    • 3. repolorizing phase: Na channels and K channels are open. getting more negative
    • 4. hyperpolorization phase: Na is blocked out but K is kept flowing making it super negative
  2. absolute refractory
    Both Na nonactivation gates and activation gates are open and you couldnt get action potential again no matter what.
  3. relative refractory period
    If theres a high enough level you could get it to action potential again but it has to be big enough
  4. membrane potential
    A change in this starts a signal
  5. graded current
    travel only short distances because it uses defussion like sound (him wispering lol) ex. dendrites to soma
  6. action potentials
    travel much greater distance (him saying a message then the next person says it like telephone) ex. axon hillock to axon terminals
  7. continues propragation
    unmyelinated fibers is very slow 1 m/s
  8. saltatory propragation
    mylinated neurons much faster and overall less energy is consumed.
  9. Type A fibers (axons)
    • largest diameters
    • velocity= 268 MPH
    • myelinated
  10. type B fibers Axon
    • smaller diameter
    • velocity= 40 MPH
    • myelinated
  11. Type C fiber (axon)
    • smallest diameter
    • velocity= 2 MPH
    • unmyelinated
  12. cholinergic fibers
    axons that release the ACh or acetalcholine neurotransmitter
  13. adrenergic fibers
    axons that release the neurotransmitter norepinephrine
  14. cholinergic receptors
    • 2 different types of receptores that recieve a specific neurotransmitter
    • nicotinic- skeletal muscle many different types ACh stimulatory
    • muscarinic- found in the parasympathetic that slows down the hearts heart rate. AcH stimulatory and inhibitory.
  15. Adrenergic receptors
    • 2 types of different receptors that are stimulated by different neurotransmitters
    • Alpha- stimulated by norepinephrine and epinephrine
    • Beta- also the epinephrines 3 different types can be found on the cell membrane. sympathetic nervous system with heart makes the heart rate higher.
  16. sympathetic nervous system
    fight or flight response and maintains blood pressure