1. Tubular Reabsorption
Figure 27-1;
Guyton and Hall

2. Primary Active Transport of Na+
Figure 27-2;
Guyton and Hall

3. Mechanisms of Secondary Active Transport
Figure 27-3;
Guyton and Hall

4. Glucose Transport Maximum
Figure 27-4;
Guyton and Hall

5. Reasorption of Water and Solutes is Coupled to Na+ Reabsorption
Interstitial
Fluid
Tubular
Cells
Tubular
Lumen
- 70 mV
Na +
H +
Na +
glucose, amino
acids
Na +
ATP K+
Urea
Na +
H20
ATP
Na + K+
Cl-
0 mv
- 3 mV
Copyright © 2006 by Elsevier, Inc.

6. Mechanisms by which Water, Chloride, and Urea Reabsorption are Coupled with Sodium Reabsorption
Figure 27-5;
Guyton and Hall

7. Cellular Ultrastructure and Primary Transport Characteristics of Proximal Tubule
Figure 27-6; Guyton and Hall

8. Cellular Ultrastructure and Transport Characteristics of Thin and Thick Loop of Henle
very permeable
to H2O)
not permeable
to H2O)
Figure 27-8;
Guyton and Hall

9. Sodium Chloride and Potassium Transport in Thick Ascending Loop of Henle
Figure 27-9;
Guyton and Hall

10. Countercurrent Multiplier System in the Loop of Henle
Figure 28-3; Guyton and Hall

11. Countercurrent multiplier animation

12. Recirculation of Urea Absorbed from Medullary Collecting Duct into Interstitial Fluid
Figure 28-5; Guyton and Hall

13. Net Effects of Countercurrent Multiplier
1. More solute than water is added to the renal medulla
(i.e., solutes are “trapped” in the renal medulla).
2. Fluid in the ascending loop is diluted.
3. Horizontal gradient of solute concentration established
by the active pumping of NaCl is “multiplied” by countercurrent flow of fluid.

14. The Vasa Recta Preserve Hyperosmolarity of Renal Medulla
serve as
countercurrent
exchangers
Vasa recta blood
flow is low
(only 1-2 % of
total renal
blood flow)
Figure 28-3; Guyton and Hall

15. Sodium Chloride Transport in Early Distal Tubule
Figure 27-10;
Guyton and Hall

16. Cellular Ultrastructure and Transport Characteristics of Early and Late Distal Tubules and Collecting Tubules
not permeable
to H2O
not very
permeable to
urea
permeability
to H2O
depends on ADH
not very
permeable to
urea
Figure 27-11; Guyton and Hall

17. Sodium Chloride Reabsorption and Potassium
Secretion in Collecting Tubule Principal Cells
Figure 27-12;
Guyton and Hall

18. Cortical Collecting Tubules
Intercalated Cells
Tubular Cells
Tubular Lumen
H20 (depends on
ADH)
H + K+
ATP
ATP K+
Na + H+
ATP
ATP K+
ATP
Cl -
Copyright © 2006 by Elsevier, Inc.

19. Cellular Ultrastructure and Transport Characteristics of Medullary Collecting Tubules
Figure 27-13; Guyton and Hall

20. Normal Renal Tubular Na+ Reabsorption
(1789 mEq/d)
7 %
(16,614 mEq/day)
65 %
25,560
mEq/d
25 %
(6390 mEq/d)
2.4%
(617 mEq/day)
0.6 %
(150 mEq/day)
Copyright © 2006 by Elsevier, Inc.

21. Summary of Water Reabsorption and Osmolarity in Different Parts of the Tubule
Proximal Tubule: 65% reabsorption, isosmotic
Desc. loop: 15-20% reabsorption, osmolarity increases
Asc. loop: 0% reabsorption, osmolarity decreases
Early distal: 0% reabsorption, osmolarity decreases
Late distal and coll. tubules: ADH dependent
water reabsorption and tubular osmolarity
Medullary coll. ducts: ADH dependent water reabsorption and tubular osmolarity

22. Minimal urine concentration
Concentration and
Dilution of the Urine
Maximal urine concentration
= mOsm / L
(specific gravity ~ 1.030)
Minimal urine concentration
= mOsm / L
(specific gravity ~ 1.003)

23. Obligatory Urine Volume
The minimum urine volume in which the excreted
solute can be dissolved and excreted.
Example:
If the max. urine osmolarity is 1200 mOsm/L,
and 600 mOsm of solute must be excreted each
day to maintain electrolyte balance, the
obligatory urine volume is:
600 mOsm/d
1200 mOsm/L
= L/day

24. Maximum Urine Concentration of Different Animals
Animal Max. Urine Conc. (mOsm /L)
Beaver
Pig 1,100
Human 1,400
Dog 2,400
White Rat 3,000
Kangaroo Mouse ,000
Australian Hopping Mouse ,000

25. H20 (w/o ADH) Aldosterone Late Distal, Cortical and Medullary
Collecting Tubules
Principal Cells
Tubular Lumen
H20 (w/o ADH)
Na +
Na +
ATP
ATP K+ K+
Cl -
Aldosterone
Copyright © 2006 by Elsevier, Inc.

26. Abnormal Aldosterone Production
Excess aldosterone - Conn’s syndrome
Na+ retention, hypokalemia, alkalosis,
hypertension
Aldosterone deficiency - Addison’s disease
Na+ wasting, hyperkalemia, hypotension,
death if untreated

27. Ang II Increases Tubular Na+ Transport
Cells
Interstitial
Fluid
Tubular
Lumen
Ang II
Ang II +
Na+ Na
ATP K + H+
Copyright © 2006 by Elsevier, Inc.

28. Ra Re Effect of Angiotensin II on Peritubular Capillary Dynamics
Glomerular
Capillary
Peritubular
Capillary Ra Re
Arterial
Pressure Re
Pc (peritubular cap. press.)
Ang II
renal blood flow FF c

29. Ang II Constriction of Efferent Arterioles Causes Na+ Retention and Maintains Excretion of Waste Products
Na+ depletion
Ang II
Resistance efferent arterioles
Glom. cap. press
Renal blood flow Peritub. Cap. Press.
Prevents decrease
in GFR and
retention of
waste products
Filt. Fraction
Na+ and H2O Reabs.
Copyright © 2006 by Elsevier, Inc.

30. Angiotensin II Blockade Decreases Na+ Reabsorption and Blood Pressure
ACE inhibitors (captopril, benazipril, ramipril)
Ang II antagonists (losartan, candesartin, irbesartan)
decrease aldosterone
directly inhibit Na+ reabsorption
decrease efferent arteriolar resistance
Natriuresis and Diuresis Blood Pressure

31. Formation of a Dilute Urine
Continue electrolyte reabsorption
Decrease water reabsorption
Mechanism: decreased ADH release and reduced water permeability in distal and collecting tubules
Figure 28-1; Guyton and Hall

32. Formation of a Concentrated Urine
Continue electrolyte reabsorption
Increase water reabsorption
Mechanism:
Increased ADH release which increases water
permeability in distal and collecting tubules
High osmolarity of renal medulla
Countercurrent flow of tubular fluid

33. Formation of a Concentrated Urine when Antidiuretic Hormone (ADH) Levels are High
Figure 28-4; Guyton and Hall

34. Osmoreceptor– antidiuretic hormone (ADH) feedback mechanism for regulating extracellular fluid osmolarity
Figure 28-8;
Guyton and Hall

35. ADH synthesis in the neurons of hypothalamus, release by the posterior pituitary, and action on the kidneys
Figure 28-9;
Guyton and Hall

36. Factors that Decrease ADH Secretion
Decreased osmolarity
Increased blood volume (cardiopulmonary reflexes)
Increased blood pressure (arterial baroreceptors)
Other factors:
- alcohol
- haloperidol (antipsychotic, tics,Tourette’s)

37. Stimuli for Thirst Increased osmolarity Decreased blood volume
(cardiopulmonary reflexes)
Decreased blood pressure
(arterial baroreceptors)
Increased angiotensin II
Other stimuli:
- dryness of mouth

38. Factors that Decrease Thirst
Decreased osmolarity
Increased blood volume
(cardiopulmonary reflexes)
Increased blood pressure
(arterial baroreceptors)
Decreased angiotensin II
Other stimuli:
-Gastric distention

39. Atrial Natriuretic Peptide (ANP)
Blood volume
ANP
Renin release aldosterone GFR
Ang II
Renal Na+ and H2O reabsorption
Na+ and H2O excretion

40. Late Distal and Collecting Tubules
Tubular Cells
Tubular Lumen
H20 (depends
on ADH)
H20
Aquaporin-2
Aquaporin-3
Aquaporins
ADH
cAMP
Vesicle
V2 receptor
Copyright © 2006 by Elsevier, Inc.

41. Sodium Chloride and Potassium Transport in Thick Ascending Loop of Henle
Figure 27-9;
Guyton and Hall

42. Sodium Chloride Transport in Early Distal Tubule
Figure 27-10;
Guyton and Hall

43. Sodium Chloride Reabsorption and Potassium
Secretion in Collecting Tubule Principal Cells
Figure 27-12;
Guyton and Hall