Distal Convoluted Tubules - Renal Physiology by Ninja Nerd

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Last edited: 3/25/2022

DISTAL CONVOLUTED TUBULE
Distal Convoluted Tubule Medical Editor: Mariel Antoinette L. Perez


OUTLINE
I) RECAP II) DISTAL CONVOLUTED TUBULE III) APPENDIX
(A) PROXIMAL CONVOLUTED TUBULE PCT (A) EARLY DISTAL TUBULE IV) REVIEW QUESTIONS
(B) LOOP OF HENLE (B) LATE DISTAL TUBULE V) REFRENCES


I) RECAP




(A) PROXIMAL CONVOLUTED TUBULE
(PCT)

AfraTafreeh.com Tubular Reabsorption
Tubular Secretion

(B) LOOP OF HENLE
Descending Limb
Ascending Limb
o Na+/K+/2Cl– transporters
 Pushes these solutes out into the
medullary interstitium
(Salty; high osmolality)
 Some K+ gets pushed back in the lumen,
creating a depolarization on the inner
side of the membrane of the ascending
limb
• Causes Mg2+ and Ca2+ to undergo
paracellular transport
Salty medullary interstitium  water is pulled
out
Importance:
o In the PCT
 65% of water was reabsorbed
 65% of sodium was reabsorbed
 300 mosm
o In the descending limb,
 15% of water was absorbed
 300 mosm  500  700  900  1200
o Going into Distal Convoluted Tubule (DCT),
 There’s only ~20% water left
 There’s only ~10% sodium left (25% of
sodium was reabsorbed in the thick
ascending limb of the loop of Henle)
 100-200 mosm
Counter-Current Multiplier Mechanism
o Maintained by the vasa recta
 Counter-current exchanger




DISTAL CONVOLUTED TUBULE RENAL PHYSIOLOGY: Note #4. 1 of 4