3 Kidney Tubule Flashcards
(33 cards)
Which cells in the collecting duct play an important role in Na+ reabsorption?
Principal cells
Which cells in the collecting duct play an important role in regulating acid/base balance?
Intercalated cells
What are the two steps of reabsorption in the kidney tubule?
1) Substances are actively or passively extracted from tubular fluid into interstitium
2) Substances are transported from the interstitium into the blood stream
Does secretion occur primarily due to active or passive transport?
Active transport
Secretion plays a major role in regulating balance of what?
K+ levels and acid/base balance
What is the average amount of fluid filtered daily? Excreted daily?
180 liters filtered per day, 1-2 liters excreted per day
What solute transporter is common to all tubule cells?
Na+/K+ ATPase
Where is the Na+/K+ ATPase located in the cell, and what is its primary function?
Basolateral membrane; establishes electric charge gradient
Is transport in the distal nephron primarily transcellular, or paracellular?
Transcellular due to the presence of tight junctions
Name some examples of Na+ reabsorption transporters.
1) Na+ glucose cotransporter
2) Na+ H+ exchanger
3) Na+ phosphate cotransporter
4) Na+ lactate cotransporter
5) Na+ calcium exchanger
Which cells in the collecting duct play an important role in regulating acid/base balance?
Intercalated cells
Is transport in the PCT primarily transcellular or paracellular?
Paracellular
In which segment of the nephron does iso-osmotic reabsorption of solutes and water occur?
PCT
What is obligatory water movement?
The movement of water following ions into the interstitial space between tubule and capillary
What is Solvent drag?
The movement of solutes from the tubular lumen into the interstitium following water
What are the four primary functions of tubular secretion?
1) Movement of drugs into the urine
2) Movement of excess urea and uric acid into the urine
3) Removal of excess K+ from blood
4) Regulation of pH (via H+ ion removal)
What main transport proteins are responsible for K+ secretion?
K+ channels and K+/Cl- cotransporter
T/F: Urine is concentrated in the PCT
F: 67% of filtrate is reabsorbed iso-osmotically; neither concentration nor dilution of urine occurs in the PCT
In which section of the nephron is the majority of Na+, HCO3-, amino acids, and glucose reabsorbed?
PCT
Which segment of the nephron, known as the diluting segment, is very permeable to solutes and relatively impermeable to water?
Thick ascending limb
Which ion transporter is inhibited by the loop diuretic furosemide, and where is it located?
Na+/K+/2Cl- symporter, apical membrane of thick ascending limb
Which segment of the nephron is freely permeable to water and relatively impermeable to solutes?
Descending limb
What percentage of solutes is reabsorbed in the TAL?
25%
Where is urine concentrated in the nephron?
Late segment of DCT and Collecting duct
