The document discusses the proximal convoluted tubule (PCT) of the nephron, highlighting its role in the resorption of essential substances such as NaCl, K, and water, with 70% of water being reabsorbed through osmosis. It also covers glucose resorption via the Na+-glucose co-transporter (SGLT-2) and the implications of SGLT-2 blockers in diabetes treatment, including potential side effects. Additionally, it introduces concepts such as transport maximum and renal threshold for glucose, along with the assessment of resorption efficiencies using TF/P values.

1. PCT
RENAL PHYSIOLOGY

5. pct

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

9. PCT WATER RESORPTION
• Water follows sodium
• Osmosis
• So 70% water is reabsorbed in PCT
• It is not under any hormonal control
• Obligatory water reabsorption
• 100% complete resorption= glucose

13. PCT GLUCOSE RESORPTION
• Channel protein called Na+– Glucose Co-transporter (SGLT-2)
• Transports sodium and glucose together
• Secondary active transport
• SGLT-2 BLOCKERS Glucose excreted in urine
• In treatment of diabetes mellitus
• Glifosins = Cana-glifosin, Dapa-glifosin, empa-glifosin
• Side effect= UTI

14. PCT- SGLT-2- CHANNEL
• SATURATION
• Transport of glucose stops
when the channel reaches saturation
Tm= Transport maximum of
Glucose
=375mg/min

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

16. Tubular fluid/ plasma fluid
• To assess the resorption of PCT
• TF/P VALUES
• TF/P=1
• Substance absorbed as same as water
• Seen in Na+ osmolarity
• Fluid in PCT is isotonic with water
• TF/P<1
• Substance reabsorbed more than water
• Seen in glucose
• TF/P>1
• Substance reabsorbed less than water
• Seen in inulin

17. Secretion of H+ & reabsorption of
hco3-

21. Thank you