1. 8 December 2010 Renal Physiology
Lab this week: Urinalysis
Review website for instructions.
Avoid caffeine on lab day, come to lab well hydrated.
Exam options: Tuesday PM, Thursday AM, Friday AM

2. Fig a
14.02a.jpg

3. Calculating clearance
Clearance of s = Urine concentration of s X Urine Volume
Plasma concentration of s
“24 hour urine catch” + blood sample
Special cases: Clearance of
Inulin and creatinine (filtered only; use to measure Glomerular Filtration Rate.)
Para Amino Hippurate (filtered and completely secreted, use to measure Renal Plasma Flow)

4. Clearance of Inulin is 120 ml/min
Clearance = volume of plasma from which a substance is completely removed (cleared) by the kidneys per unit time.
Clearance of Inulin is 120 ml/min
Cinulin or Ccreatinine = Glomerular Filtration Rate
If C x is greater than GFR ( which is Cinulin) then that substance undergoes NET TUBULAR SECRETION
If C x is less than GFR ( which is Cinulin) then that substance undergoes NET TUBULAR REABSORPTION

5. Renal Handling Net Reabsorption Ex: Sodium Complete Reabsorption
Ex: Glucose
Net Secretion
Ex: PAH & RPF

6. Reabsorption and secretion in proximal tubule is NOT under hormonal control.
Primary active transport of Na+ establishes a gradient for reabsorption of glucose, amino acids, etc.
Reabsorption and secretion in DCT & CD is under hormonal control.
Hormones that act here: ANH, ADH, Aldosterone.
Here, reabsorption of Na+ is linked to the secretion of K+.

7. Effect of Aldosterone: insertion of more Na+K+ATPase into basolateral membrane
Effect: Increase Na+ reab and Increase K+ Secretion

8. Figure 14.30
Apply this information to each of the three Test Beverages used in the Urinalysis Lab!
Cell in the adrenal cortex that respond to AII are also receptors for plasma K+ concentration.
Sodium reabsorption and potassium secretion are coupled.

9. Effect of ADH: insertion of more aquaporins in th the membranes
Effect: Increase H2O reabsorption

10. Figure 14.31
Normally, all filtered bicarbonate is “reabsorbed”