ABSTRACT
Using a straight line to represent the length of the proximal convoluted tubule (PCT), from the Bowman’s capsule to the start of the loop of Henle, show the glucose, sodium and inulin concentrations. Explain the diagram and the physiology involved. Renal handling of glucose, inulin and sodium https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315384207/e44fc968-d9a2-42bd-a238-aaa8f50c7f02/content/fig29_1_OB.tif"/>
In health, glucose is completely reabsorbed so its concentration falls to zero along the length of the PCT (sharp decline in the first part of the PCT, with slower decline further down).
Sodium is almost completely reabsorbed and is followed by passive diffusion of water, so its concentration remains unchanged (straight line).
Inulin is filtered but not reabsorbed, so its concentration rises (sloped positive curve).
Renal handling of various substances in filtrate per 24 hoursSubstance
Filtered
Reabsorbed
Secreted
Excreted
Percentage reabsorbed
Location*
Na+ (meq)
26 000
25 850
150
99.4
P, L, D, C
K+ (meq)
600
560
50
90
93.3
P, L, D, C
Urea (mmol)
870
460
410
53.0
P, L, D, C
Creatinine (mmol)
12
1
1
12
P, L, D, C
Glucose (mmol)
800
800
100.0
P
Water (mL)
180 000
179 000
1000
99.4
P, L, D, C
P = proximal tubules; L = loops of Henle; D = distal tubules; C = collecting ducts.
