PCT- Renal physiology

Proximal convoluted tubules
functions, resorption, secretion
SGLT2 channels, the renal threshold of glucose, tubular fluid to plasma ratio, obligatory water resorption, urine formation.
Hydrogen ion secretion and bicarbonate absorption
renal glycosuria, diabetes mellitus

1. PCT
RENAL PHYSIOLOGY

5. pct

6. PCT
•Part of nephron related to maximum resorption.
•Brush border. More area. More resorption
•Inside ofcell= more mitochondria. Resorption(active)
•70% NaCl resorbed here
•70%Kreabsorbed
m
m
m
m
ATP

9. PCT WATER RESORPTION
•Water follows sodium
•Osmosis
•So 70% water is reabsorbed in PCT
•Itisnotunder any hormonal control
•Obligatorywaterreabsorption
•100%completeresorption= glucose

13. PCT GLUCOSE RESORPTION
•Channelprotein called Na+–Glucose Co-transporter (SGLT-2)
•Transportssodiumandglucose together
•Secondaryactivetransport
•SGLT-2BLOCKERS Glucose excreted in urine
•In treatment ofdiabetesmellitus
•Glifosins= Cana-glifosin, Dapa-glifosin, empa-glifosin
•Side effect= UTI

14. PCT-SGLT-2-CHANNEL
•SATURATION
•Transportofglucosestops
whenthechannelreachessaturation
Tm=Transportmaximumof
Glucose
=375mg/min

15. RENAL THRESHOLD/
RENAL GLYCOSURIA
•=200mg/dl
•After 200mg/dl, glucose starts
appearing in urine.

16. Tubularfluid/ plasmafluid
•ToassesstheresorptionofPCT
•TF/PVALUES
•TF/P=1
•Substanceabsorbedassameaswater
•SeeninNa+osmolarity
•FluidinPCTisisotonicwithwater
•TF/P<1
•Substancereabsorbedmorethanwater
•Seeninglucose
•TF/P>1
•Substancereabsorbedlessthanwater
•Seenininulin

17. SecretionofH+ & reabsorptionof
hco3-

21. Thank you