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The Na + -K + ATPase Pump

The Na + -K + ATPase Pump. Cardiac glycosides: plant and animal steroids Ouabain! Digitalis!:

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The Na + -K + ATPase Pump

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  1. The Na+-K+ ATPase Pump

  2. Cardiac glycosides: plant and animal steroids Ouabain! Digitalis!: increased Na+ conc inside heart leads to stimulation of Na+-Ca2+ exchanger, which extrudes sodium in exchange for inward movement of calcium. Increased intracellular Calcium stimulates muscle contraction.

  3. The Na+-K+ ATPase Pump: Mechanism

  4. Response of a human RBC to changes in osmolarityof the extracellular fluid

  5. The Na+-K+ ATPase Pump is required to maintain Osmotic Balance and Stabilize Cell VolumeSources of Intracellular Osmolarity:large number of counterions (inorganic ions of opposite charge) that are attracted to large macromolecules (most are charged).small metabolites (high concentration of small organic molecules, sugars, amino acids, nucleotides) and their counterions Sources of Extracellular Osmolarity: Due mainly to small inorganic ions - these leak slowly across the plasma membrane into the cell. The problem: Because of above factors, water moves into the cell by osmosisThe Solution:Na+-K+ ATPase Pump

  6. In vitro Investigation ofThe Na+-K+ ATPase Pump

  7. Control of acid secretion in the stomach

  8. Potassium channel

  9. The Potassium Channel

  10. Hinge-bending Model for the opening of the Bacterial KcsA Channel.

  11. The Structure of One subunit of a eukaryotic, Voltage Gated K+ Channel (Drosophila Shaker K+ Channel)

  12. 3-D Structure of a Voltage Gated Mammalian K+ Channel

  13. Conformational States of a Voltage Gated K+ Ion Channel

  14. A typical ion channel fluctuates between open and closed states

  15. The gating of ion channels

  16. The technique of patch clamp recordingMeasuring Ion Channel Conductance

  17. Patch Clamp Recording

  18. Patch Clamp Recording

  19. The ionic basis of membrane potential

  20. The membrane potential in animal cells depends mainly on K+ Leak channels and the K+ gradient across the plasma membrane

  21. dGconc= -RT ln [Co] [Ci]

  22. dGvolt=zFV

  23. dGconc + dGvolt = 0Ion distribution is at equilibrium across the membrane

  24. The Nernst Equation and Ion FlowV= RT ln Co zF Ci

  25. The Resting Potential decays only slowly when the Na+ K+ Pump is stopped

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