How many moles of sodium are filtered in the Bowman's capsule a day?
How many moles of sodium are excreted a day?
How many litres of blood are filtered a day?
How many litres of urine are produced a day?
What happens to the sodium and water that are not excreted?
Reabsorbed in the tubules
What are the sites of reabsorption in the tubule?
PCT -> PST -> DTLLH -> TALLH -> DCT -> Collecting duct
What reabsorption happens in the PCT?
50% water and 50% sodium is reabsorbed Isotonic
What reabsorption happens in the PST?
20% water and 20% sodium Isotonic
What reabsorption happens in the DTLLH?
What reabsorption happens in the ATLLH?
What reabsorption happens in the DCT?
What reabsorption happens in the collecting duct?
4% sodium 19% water
In which parts of the tubule is reabsorption isotonic?
PCT and PST
Which parts of the tubule are impermeable to water?
TALLH and DCT
What separates the lumen and interstitial fluid in a renal epithelial cell?
What controls most reabsorption in the renal epithelial cells?
What controls movement of sodium in and out of renal epithelial cells?
Sodium potassium pump
What does the lumen refer to?
What does the interstitial milieu refer to?
What substances are reabsorbed in the PCT along with sodium?
Glucose Amino acids Phosphate Chlorine Protons Water
What type of transporters control the movement of these molecules along with sodium?
Most are symporters Protons - sodium - proton antiporter Chlorine - channel Water - aquaporins
What feature makes cells permeable to water?
Presence of aquaporins
What is the role of the TDLLH in controlling salt and water reabsorption?
Mainly control equilibration of sodium and water via channels and aquaporins
Is the process of reabsorption in the TALLH active?
Yes - requires lots of ATP
What type of cotransporter is uniquely present on epithelial cells of the TALLH?
2-chloride, potassium, sodium cotransporter
What does the potassium transporter on TALLH epithelial cells do?
Why is a positive transepithelial potential created in TALLH epithelial cells?
Chlorine is transported into the blood - 2 chlorines for every sodium Transporting more chlorine ions than sodium = positive transepithelial potential
What does this positive transepithelial potential do?
Transports additional chlorine, sodium, potassium and calcium through a paracellular shunt
Which cells of the collecting duct regulate water and sodium reabsorption?
ENaC - epithelial sodium channel ROMK - Renal Outer Medullary Potassium Channel
Is water and sodium permeability regulated in collecting duct epithelial cells?