2 December 2011
Renal Physiology
Test # 3 Monday Dec 5th
Lab Next Week: Urinalysis
Options:
800 ml tap water
800 ml tap water + 7 g NaCl
80 ml tap water + 7 g NaCl
None of the above
Urinalysis Lab Day
Drink plenty of water the day of lab;
Avoid coffee, caffeine, salty foods
60 min
1 Hr
before Lab
Empty
bladder;
note time
Drink
Test
Beverage
30 min
800 ml tap water
800 ml tap water + 7 g NaCl
80 ml tap water + 7 g NaCl
30 min
30 min
30 min
At 30 min
intervals,
collect urine
measure V
and [NaCl]
Beginning of Lab:
Collect Urine, measure Volume and titrate for [NaCl]
30 min
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?
Membrane proteins are
segregated into apical (luminal)
and basolateral membranes.
Figure 14.10
reabsorption
secretion
Amino acid
metabolism
glucose
Filtration is controlled by aa and ea diameters!
Consider a substance that in filtered only, no reabsorption, no secretion.
Excretion of this substance = GFR
Clearance 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
Renal Handling of Substances
Filtration +
complete Secretion
Ex: Para AminoHippurate (PAH)
Measure Renal Plasma Flow
Filtration + partial reabsorption
Filtration + 100 Reabsorption
Ex: Sodium
Ex: Water
Ex: Glucose
Ex: Amino Acids
• 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
Renal Handling of Substances
Filtration +
complete Secretion
Ex: Para AminoHippurate (PAH)
Measure Renal Plasma Flow
Filtration + partial reabsorption
Filtration + 100 Reabsorption
Ex: Sodium
Ex: Water
Ex: Glucose
Ex: Amino Acids
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 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)
Who Cares?
S 17
Sonogram showing
fluid-fill cavities
within the kidney
Dr. Davis’s lovely bride of 30+ years
S 18
Fluid-filled cysts
Polycystic
Kidney
Disease
Symptoms?
Genetics?
Prognosis &
Treament?
Fig. 14.04
PKD is an
autosomal
dominant:
pp
X
P?
Measure Ccreatinine
To chart the
progress of the
disease.
End of Material for
Test # 3
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+.