2 December 2011Renal Physiology

Test # 3 Monday Dec 5th

Lab Next Week: Urinalysis

Options:800 ml tap water800 ml tap water + 7 g NaCl80 ml tap water + 7 g NaClNone of the above

1 Hrbefore LabEmpty bladder; note time

Beginning of Lab:Collect Urine, measure Volume and titrate for [NaCl]

Drink Test Beverage

At 30 min intervals, collect urinemeasure V and [NaCl]

30 min 30 min30 min30 min30 min

Drink plenty of water the day of lab;Avoid coffee, caffeine, salty foods

60 min

800 ml tap water800 ml tap water + 7 g NaCl80 ml tap water + 7 g NaCl

Urinalysis Lab Day

1QQ 33 for 8:30

1. How does the composition of the ultrafiltrate in Bowman’s space differ from plasma? If glucose concentration in the plasma is 70 mg/ml, what will the glucose concentration be in the ultrafiltrate in Bowman’s space?

2. What is the location and role of macula densa cells?

3. Which segments of the nephron are found in the medulla?

4. What are two ways by which GFR can be increased?

1QQ 33 for 9:30

1. How does the composition of the ultrafiltrate in Bowman’s space differ from plasma? If glucose concentration in the plasma is 100 mg/ml, what will the glucose concentration be in the ultrafiltrate in Bowman’s space?

2. What is the location and role of macula densa cells?

3. Which segments of the nephron are found in the medulla?

4. What are two ways by which GFR can be decreased?

Figure 14.10

Membrane proteins are segregated into apical (luminal) and basolateral membranes.

reabsorption

secretionmetabolism

Amino acid glucose

Filtration is controlled by aa and ea diameters!

Consider a substance that in filtered only, no reabsorption, no secretion.

Excretion of this substance = GFRClearance of this substance = GFR

• Clearance = volume of plasma from which a substance is completely removed (cleared) by the kidneys per unit time.

• Two substances that are only filtered: Inulin and Creatinine

• Cinulin or Ccreatinine = Glomerular Filtration Rate

• Clearance of Inulin is 120 ml/min

Filtration + complete Secretion

Ex: Para AminoHippurate (PAH)

Measure Renal Plasma Flow

Filtration + partial reabsorption

Ex: SodiumEx: Water

Filtration + 100 Reabsorption

Ex: GlucoseEx: Amino Acids

Renal Handling of Substances

• Clearance allows us to determine how the kidneys are handling a substance (net secretion or net reabsorption.)

• 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

Filtration + complete Secretion

Ex: Para AminoHippurate (PAH)

Measure Renal Plasma Flow

Filtration + partial reabsorption

Ex: SodiumEx: Water

Filtration + 100 Reabsorption

Ex: GlucoseEx: Amino Acids

Renal Handling of Substances

A little more on Clearance:

Clearance of glucose = 0 ml/min which means….

Clearance of X = 120 ml/min which means….

Clearance of antibiotic XXX = 500 ml/min which means…

Calculating clearanceClearance of s = Urine concentration of s X Urine Volume

Plasma concentration of s

Special cases: Clearance of

•Inulin and creatinine (filtered only; use to measure Glomerular Filtration Rate.)

•Para Amino Hippurate (filtered and completelysecreted, use to measure Renal Plasma Flow)

“24 hour urine catch” + blood sample

Who Cares?

S 17

Sonogram showingfluid-fill cavities within the kidney

Dr. Davis’s lovely bride of 30+ years

Fig. 14.04Fluid-filled cysts

Polycystic Kidney DiseaseSymptoms?Genetics?Prognosis & Treament?

S 18

PKD is an autosomal dominant:

pp X P?

End of Material for

Test # 3

Measure Ccreatinine

To chart the progress of thedisease.

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+.