Renal stuff Flashcards
In which part of the tubule are water and sodium being removed at a similar pace?
Proximal tubule - osmolality remains constant
In which part of the tubule is 65% of the water that was initially filtered into Bowman’s capsule being removed?
Proximal tubule - 35% of the water is left by the time the filtrate has passed through the proximal tubule.
Is the descending loop of Henle permeable to water, sodium, both, or neither?
Descending loop of Henle is permeable only to water. The graph shows the osmolality (number of particles relative to the amount of water) greatly increasing in the first half of the loop of Henle (descending). The absolute number of particles, sodium, is staying the same but the amount of water is going waaaay down because water is leaving the tubule.
Is the ascending loop of Henle permeable to water, sodium, both, or neither?
The second half of the loop of Henle, the ascending part, is permeable only to sodium. The graph shows the osmolality going way down - the amount of water is staying the same but the number of particles (sodium) is greatly decreasing.
Where is the decision point as to how much water we want to keep or not keep?
As we enter the collecting duct.
What segment of the tubule is sensitive to ADH?
Collecting duct
What happens to the osmolality of the urine if the maximal amount of ADH is present?
The maximum amount of water possible is reabsorbed from the filtrate, so therefore the osmolality (number of solute particles per amount of water) goes way up.
How much of the original filtrate that we got in Bowman’s capsule escapes as urine if we don’t utilize any ADH?
20%
What substances are entirely removed from the filtrate by the time the filtrate leaves the PROXIMAL TUBULE?
amino acids
glucose
lactate
What two substances are removed from filtrate at equal rates as each other while passing through the PROXIMAL TUBULE?
sodium and water
What happens to inorganic phosphate in filtrate that is passing through the proximal tubule? (reabsorbed, not reabsorbed)
There is some reabsorption of inorganic phosphate in the proximal tubule but there is still phosphate in the filtrate when the filtrate leaves the proximal tubule.
What happens to bicarbonate in filtrate that is passing through the proximal tubule? (reabsorbed, not reabsorbed)
There is some reabsorption of bicarbonate in the proximal tubule but there is still bicarb in the filtrate when the filtrate leaves the proximal tubule.
What is the fate of penicillin in the kidney tubule?
Actively secreted in proximal tubule.
Organic nutrients and proteins - we want to keep these! What happens to them in the kidney tubule?
Organic nutrients, proteins, phosphates, and sulfates are all actively reabsorbed in the proximal tubule.
If we miss reabsorbing some organic nutrients, proteins, phosphates, or sulfates in the proximal tubule, it’s no big deal - we can just reabsorb them later.
True or false?
FALSE! There is nowhere else along the tubule where we can reabsorb these! Get it done in the proximal tubule!
What do we do with hydrogen ions in the kidney tubule?
At every point in the tubule we are trying to RID ourselves of H+….SECRETE, SECRETE, SECRETE! There’s no point in the tubule where we reabsorb these, but every segment secretes them.
In general, what is the fate of electrolytes in the kidney tubule?
REABSORB all along the tubule (not counting hydrogen or ammonium, but yes sodium, calcium, bicarbonate, chloride, potassium*)
*potassium is reabsorbed at every segment except distal
