1. صدق الله العظيم الاسراء اية 58

2. By Dr. Abdel Aziz M. Hussein Lecturer of Medical Physiology

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5. 5 Abdelaziz Hussein (Na-K ATPase) Na-K pump Ca-ATPase (Ca-pump) K-H-ATPase (proton pump) SiteCell membranes. Sarcoplasmic reticulum and cell membranes. Stomach parietal-cells and renal distal tubular cells. ImportanceMaintains low intracellular Na and high intracellular K. Maintains the intracellular Ca ions concentration low. Transports H ions into the lumen against its electrochemical gradient.

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9. Na Pump Animation Active Transport Na + /K + -ATPase Jens Skou - 1957 Nobel 1997

10. Site Site: cell membrane Composition: : Composition: : 2 subunits ;  Beta subunit: anchoring subunits.  Alpha subunit: has: a.ATPase property (ability to split ATP). b.ATP binding site c.Na binding site→ inner surface d.K binding site→ outer surface of the cell membrane. 10 biophysics, Abdelaziz Hussein

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13. Operation : Operation : 2 steps a.Phosphorylation step: for transport of 3 Na ions b.Dephosphorylation step: for transport of 2 K ions 13 biophysics, Abdelaziz Hussein

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15. 15 biophysics, Abdelaziz Hussein Start

16. Phosphorylation step 16

17. 17 Biophysics, Abdelaziz Hussein Na ions K ions ATP ADP P

18. 18 Biophysics, Abdelaziz Hussein Na ions K ions P

19. Dephosphorylation step 19

20. 20 Biophysics, Abdelaziz Hussein Na ions K ions P

21. 21 Biophysics, Abdelaziz Hussein Na ions K ions ATP

22. Function of Na-K pump: It transports Na from ICF to ECF and K from ECF to ICF→ maintains low intracellular Na and high intracellular K. It utilizes about 40% - 50% of energy. 22 biophysics, Abdelaziz Hussein

23. Control of its activity: 23 biophysics, Abdelaziz Hussein ActivatorsInhibitors High intracellular NaLow intracellular Na High extracellular KLow extracellular K Availability of ATPLow ATP Hormones as thyroxine, insulin and aldosterone Drugs as dopamine and cardiac glycosides as Oubain and digitalis → interfere with dephosphorylation step.

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25. Na+ Low Ca++ High Ca++ K+ Na+ Glucose K+ = 4 mEq/L Na+= 140 mEq/L K+ = 140 mEq/L Na+= 14mEq/L High glucose Low Glucose ATPADP Na+ Ca++

26. 26 Abdelaziz Hussein Na-glucose co- transport Na-Ca Exchange Sitecell membranes.ventricular ms cells Importance Transport of Na & glucose into the cells It transports Ca uphill from low ICF Ca to high ECF Ca

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28. Types of Transporters 28

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30. 30 Abdelaziz Hussein Mechanism by which the large sized substances can cross the cell membranes It is active process which uses energy Vesicular Transport Endocytosis EC material engulfed and pushed into cells Exocytosis IC material is engulfed and pushed into the cell

31. 31 Abdelaziz Hussein -Extracellular material is trapped within vesicles and pushed inside the cell Phagosome

32. 32 Phagosome Lysozymes

33. 33 Abdelaziz Hussein Is 3 types; Endocytosis Phagocytosis Solid particles e.g. bacteria and dead tissues Pinocytosis Substance in solution e.g. proteins Receptor mediated Iron and cholesterol

34. 34 Abdelaziz Hussein Is active process which uses energy Intracellular material is trapped within vesicles, then the vesicles fuse with the cell membrane and release their contents to the ECF

35. 35 Abdelaziz Hussein Exocytosis Regulated Vesicles undergo processing e.g. secretion of insulin Constitutive Vesicles undergo no or little processing e.g. release of neurotransmitter

36. THANKS