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1. 1
RENAL PHYSIOLOGY
(III)
m
RENAL TUBULAR
PROCESSING
Mohammed Abdel Gawad

2. OBJECTIVES
2
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

3. OBJECTIVES
3
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

4. Formation of URINE in 3 steps
4
Tubular Tubular
Reabsorption Secretion
Glomerular Excretion
Filtration

5. RENAL CIRCULATION
5

6. Formation of URINE in 3 steps
6

7. Formation of URINE in 3 steps
7

8. OBJECTIVES
8
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

9. Cell Membrane
9
Polar heads
love water
& dissolve.
Non-polar
tails hide
from water.

10. Forms of Membrane Transport
10

11. Forms of Membrane Transport
11

12. PASSIVE TRANSPORT
12
 With concentration gradient (downhill)
 No need for energy

13. Diffusion through phospholipid bilayer
13

14. Diffusion through phospholipid bilayer
14
inside cell
lipid
K O2
Na glucose a.a. CO2
outside cell

15. Leak Channels
15

16. Leak Channels
16
high
low

17. Facilitated Diffusion
17

18. Facilitated Diffusion
18
high
low

19. ACTIVE TRANSPORT
19
• Against concentration gradient (UPhill)
• need energy (ATP, CP)

20. Primary Active Transport
20

21. Primary Active Transport
21

22. Secondary Active Transport
22

23. Secondary Active Transport
23

24. Secondary Active Transport
24

25. Secondary Active Transport
25
Tubular Interstitial
Tubular Tubular Cell Interstitial Tubular Cell
lumen Fluid
lumen co-transport Fluid counter-transport
(symport) (antiport)
out in out in
Na+ Na+
glucose H+
Co-transporters will move one moiety, Counter-transporters will move one
e.g. glucose, in the same direction as moiety, e.g. H+, in the opposite direction
the Na+. to the Na+.

26. Pinocytosis
26
 Some parts of the tubule, especially the proximal
tubule, reabsorb large molecules such as
proteins by pinocytosis.

27. OBJECTIVES
27
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

28. Proximal Convoluted Tubule
28

29. Proximal Convoluted Tubule
Reabsorption
29
phosphate phosphate

30. Proximal Convoluted Tubule
Reabsorption
30
 Some parts of the tubule, especially the proximal
tubule, reabsorb large molecules such as
proteins by pinocytosis.

31. Proximal Convoluted Tubule
Secretion
31

32. Proximal Convoluted Tubule
Secretion
32
 The proximal tubule is also an important
site for secretion of:
 organic acids and bases such as bile
salts,oxalate, urate, and catecholamines.
 drugs penicillin and salicylates
 toxins
 PAH

33. OBJECTIVES
33
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

34. Loop of Henle
34
(Descending Limb)

35. Loop of Henle
35
(Ascending Limb)

36. Loop of Henle
36
(Ascending Limb)

37. OBJECTIVES
37
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

38. Early Distal Convoluted Tubule
38

39. Early Distal Convoluted Tubule
39

40. Late Distal Convoluted Tubule
Collecting Duct
40

41. Late Distal Convoluted Tubule
Collecting Duct
41

42. Late Distal Convoluted Tubule
Collecting Duct
42

43. OBJECTIVES
43
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

44. Urea Tubular Handling
44

45. Sodium Tubular Handling
45
65%
8-10%
25%

46. Water Tubular Handling
46
65% by osmosis
15%
(obligatory
Under effect of
reabsorption)
ADH
(Facultative
reabsorption)
15-20%
by osmosis
(obligatory
reabsorption)

47. OBJECTIVES
47
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Hormones & Kidney Tubules
 Tubular Transport Maxima

48. Hormones & Kidney Tubules
48

49. OBJECTIVES
49
 Formation of urine
 Forms of membrane Transport
 PCT Function
 Loop of Henle Function
 DCT Function
 Urea, Na & Water Tubular Handling
 Tubular Transport Maxima

50. Tubular transport maxima (Tm)
50
 It is the maximum amount of a substance in mg, which can be
reabsorbed or secreted per minute.
 TmG with normal blood glucose level = 375 mg/min for men, 300
mg/min for women

51. 51
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52. 52
Gawad