Renal Transport Mechanisms - Pierce Flashcards
Proximal convoluted tubule reabsorbs what
100%
mostly
very little
glucose + aa = 100%
Na, K, P, Ca, H2O = 70%
only 30% Mg
where is most of the Mg reabsorbed
thick ascending limb (also Distal straight tubule)
how do solutes get reabsorbed (order of layers crossed)
- apical membrane of tubule
- Basolateral membrane of tubule
- epithelium of BV
where can you find the brush border
apical side facing lumen of tubule
things that cross apical side of PT
not H2O
- Na/glucose (SGLT)
- Na/ aa
- NA/ HCO-3
- Na/ H+ (antiport) (NHE)
things that cross basolateral side of PT
not H2O
- Na/K+ ATPase
2. HCO-, aa, glucose (GLUT), H+ , Cl- all diffuse over to BV
which BV is around the PT
peritubular capillary
how does water cross the PT
passive transport by AQP channel on both apical and basolateral
enters BV by bulk flow
when reabsorbing H2O
NA always follows
which part of the LOH is h2o permeable
the thin LOH (think ascending and thin descending)
Thick Ascending Limb (TAL) reabsorption of what
X WATER
- Na,
- K
- Ca
- Mg *
TAL reabsorption on apical side
- NKCC2 channel (Na-K-2Cl)
2. ROMK (EXCRETE K+ back to urine)
TAL reabsorption on basolateral side
- Mg+, Ca paracellulary
- Na/K ATPase
- Cl- channel
- K+ channel
what is the role of ROMK
back leak of K+ into the urine (lumen) which bulids up gradient and helps Mg and Ca paracellulary leave
Distal convoluted tubule reabsorption + role
minimal reabsorption (X WATER) MAINTAIN REGULATION site
ADH and Aldosterone act on what
principal cells of Distal convoluted tubule
3 cell types of DCT
- principal cells
- a- intercalated cells
- B-intercalated cells
principal cells role
REAB : Na+, H2O
SECRETE: K+
a- intercalated cell role
REAB : K+, HCO-3
SECRETE: H+
B- intercalated cell role
REAB : H+, Cl-
SECRETE: K+, HCO-3
DCT uses what to reabsorb at apical end
- NCC (Na, Cl-) thiazide-sensitive
- TRPV5 (ligand Ca+2 channel)
- ENaC (Na, H2O)
DCT uses what to reabsorb at basal end
- Cl- channel
- Na/K+ ATPase
- NCE (Ca+ out to BV and Na+ into cell)
principal cells use what to reabsorb Na+ and H2O
apical
ENaC on apical side
*where aldosterone binds to
principal cells use what to reabsorb Na+ and H2O
basolateral
Na/K ATPase