Urine formation by the Kidney -Tubular Processing of GF 1 Flashcards
Give example of primary active transport in the renal tubules?
Primary active transport through baso-lateral membrane (Na+/K+ ATPase pump)
What are examples of secondary active transport?
Co-transport (i.e, AA and glucose reabsorption)
Transporter simultaneously bind Na+ and glucose or AA on the apical surface and transport them into the cell
Counter-transport (i.e. secretion of H+)
What is tranport maximum (Tm)?
Tm (or transfer maximum) – the maximal amount of a given solute that can be transported (reabsorbed or secreted) per minute by renal tubules
What is threshold concentration?
plasma concentration of a solute at which it begins to appear in urine
Where are the GLUT1 and 2 carriers, what part of the renal tubule membrane are these carriers located?
baso-lateral membrane
What co-transport carriers carry Na+ and glucose across apical membrane of the early proximal and late proximal tubule?
SGLT 1 and SGLT 2
What are some reasons for glucosuria?
- ↑ plasma [glucose] (i.e., uncontrolled diabetes mellitus)
- ↑ GFR and glucose filtered load (i.e., pregnancy)
- Congenital abnormalities of Na+- glucose co-transporter
Excretion curve
Mechanism of reabsorption of urea?
simple diffusion down concentration gradient
PAH depends on the plasma concentration of unbound or bound PAH?
unbound PAH
What are the meanings of glucose transport maximum and glucose threshold concentration?
Do they change in a diabetic patient?
What are the normal values?
Can excretion of glucose exceed filtration?
When reabsorption of glucose is equal to filtration?
When excretion of glucose exceeds reabsorption?
Identify the Tm and threshold
concentration on this graph.
Answer the following question.