Urinary 2 - Renal reabsorption Flashcards
(44 cards)
Where does the majority of reabsorption occur?
Proximal Convoluted Tubule
Where does 65% H2O reabsorption occur?
PCT
Where does 100% Glucose and amino acid reabsorption occur?
PCT
What channel in the basolateral membrane drives renal reabsorption?
Na+/K+-ATPase
Name the 2 Na+ channels located on the apical membrane of the PCT:
1 - Na+-Glucose symporter (SGLUT)
2 - Na+/H+ antiporter
Name the Na+ channel located on the apical membrane of the TAL (LoH):
Na+/K+/2Cl symporter (NKCC2)
Name the Na+ channel located on the apical membrane of the early Distal Tubule:
Na+/Cl- symporter (NCC)
Name the Na+ channel located on the apical membrane of the late distal tubule and collecting ducts:
ENaC
What substances are secreted into the tubules?
- K+
- H+
- Organic anions and cations
How do anions and cations move across the apical membrane (to be secreted)?
via H+ antiporter
Name a few endogenous cations that are secreted into the tubule:
- Acetylcholine
- Dopamine
- Adrenaline
- Histamine
- Serotonin
Name a few drugs that are secreted into the tubule:
- Sulfonamines
- Morphine
- Atropine
- Isoproterenol
- Penicillin
- Salicylate
- NSAIDs
Name a few endogenous anions that are secreted into the tubule:
- Urate
- Bile salts
- Fatty acids
How are the majority of Cl- reabsorbed in the PCT?
via passive paracellular movement in S2/3 segment, down concentration gradient (no Cl- reabsorption in S1 segment)
In which part of the tubule does 67% of Na+ reabsorption occur?
PCT
Name the 3 driving forces for reabsorption from the PCT into the peritubular capillaries:
1) Osmotic gradient
2) Oncotic force (higher in peritubular capillary due to lack of protein in tubule)
3) Hydrostatic pressure (higher in interstitium, pushes solute into capillary)
What is the name of the structure which invaginates the glomerulus?
Bowman’s Capsule
Name the 2 types of nephrons:
1) Juxtamedullary
2) Cortical
What type of nephron is most common?
Cortical (80%)
How is the histology of the thin ascending LoH different to the PCT, and why?
In thin ascending LoH: - no brush border - no mitochondria - wider lumen No active transport in thin ascending LoH (^active transport in PCT)
Name the main ions reabsorbed in the distal tubule:
Na+
Ca2+
Cl-
What is reabsorbed in the descending LoH?
Only H2O
In what part of the ascending LoH does active transport occur?
Thick ascending limb (TAL)
What part of the nephron uses most energy, therefore is most susceptible to hypoxia?
Thick ascending limb of LoH (TAL)
