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2013-03-13 15:21:23
Neurons ions physiology

Physiology of neurons
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  1. Hydrophilic
    Water attaches, to it

    ex. Phosphate head of phospholipid bilayer
  2. Hydrophobic
    repelled by water

    ex. Lipid tails of phospholipid bilayer
  3. Intracellular (inside the neuron)
    • K+ , protein- (amino acids)
    •   --not equal concentration
  4. Dendrites
    • branched like extentions
  5. Extracellular (outside Neuron)
    Na+ (very positive) + mvolt
  6. Graded Potential
    • Bring Positive ions in neuron.
    • A change in the RMP
    • Occurs on the dendrites or cell body
    • + ions are depolarizing(+ions come across
  7. Polarizied
    a separation of change across a membrane
  8. Hyperpolarizing
    RMP becomes more (-)
  9. Depolarizing
    + ions come across membrane

    Becomes more positive
  10. Threshold
    Amount of depolarization required to generate an impulse (Current flowing down an axon).
  11. how do ions move across the membrane?
    by channel proteins
  12. what are the 4 channel proteins?
    1. Leak Channel

    2. Chemically Gated Channel

    3. Voltage Gated Channel

    4. Mechanically Gated Channel
  13. Leak Channel

    K+ is always leaking........

    Na+ is always leaking........
    Leak ions back and forth A.M.

    ...out of cell the cell at slower rate
  14. Chemically gated channel
    A chemical bonds to membrane to open an ion channel.
  15. Na+/K+ Exchange pump
    • Pumps
    • 3 Na+ out &
    • 2 K+ in
  16. Voltage Gated Channel
    • Respond to a change in the trasmembrane ptential ( RMP)
    • When RMP -70mV reach treshold (-55mV) Na+ gates open axon action potential