16. Glucose clearance Flashcards Preview

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Flashcards in 16. Glucose clearance Deck (12):
1

Glucose clearance - describe

glucose at a normal plasma level is completely reabsorbed in proximal concoluted tubule bby Na+/ glucose contrasport

2

glucose in serum ( normally)

fasting : 70 -110 mg / dL (3.8-6.1 mmmol/L )
2h postprandial : less τηαν 120 mg/dL , less than 6.6 mmol /L

3

glucose in cerebrospinal fluid

40-70 mg/dL
2.2-3.9 mmol/L

4

glucose in urine - concrentations ( adults

In adults, at plasmaglucose of 200 mg / dL --> glucosouria begins . At rate 375 mg/ min , all transporters are fully saturated

5

glucosuria is an importan t clinical clue to

diabetes mellitus

6

glucose clearance - splay ?

is the region of substance clearance between threshold and Tm --> it is due to heterogeneity of nephrons

7

glucose clearance - pregnancy

normal pregnancy may decreae ability of proximal conluted tubule to reabsorb glucose and aminoacids --> glucosouria and aminoaciduria

8

mechanism that induce glucosouria and aminoaciduria in normal pregnancy

normal pregnancy may decrease ability of proximal convoluted tubule to reabsorb glucose and aminoacids

9

• In the nephron, glucose is ___ (partially/fully) reabsorbed in ___ the (proximal/distal) tubules via Na+/glucose cotransporters.

Fully; proximal

10

• When plasma glucose levels exceed 200 mg/dL, what finding may result on urinalysis? What disease process is usually suspected?

Glucosuria, because proximal tubule glucose reabsorption mechanisms cannot keep up with the elevated glucose load; diabetes mellitus

11

• A diabetic's blood sugar is 275 mg/dL; the urine is positive for glucose. Can proximal tubule pumps handle further blood-sugar increases?

Yes—the glucose threshold of 200 mg/dL has been passed, but the transporters are not fully saturated (Tm) until the level passes 375 mg/dL

12

• Glucosuria and aminoaciduria develop in a pregnant woman. Do you immediately diagnose diabetes?

No—normal pregnancy decreases reabsorption of glucose and amino acids in the proximal tubule, resulting in glucosuria and aminoaciduria

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