Mechanism to Adjust Urine Concentration Flashcards
How does a loop diuretic work?
It books the Na/K, Cl cotransporter in the TAL and thus it’s disturbing the multiplier system and thus cannot concentrate the urine. Therefore, pts loose a huge amount of Na and thus water.
What are some problems that can arise due to the body’s inability to control Salt and Water Balance?
- Edema
- Disorders of plasma K concentration: hypo or hyperkalemia
- Undesirable changes in blood pressure
- Acid/base disorders
- Neurological problems: shrinking or swelling of the brain
In the PCT name ways Na is reabsorbed.
- Cotransport with glu, AA, phosphate
- Na/H exchange (countertransport)
- Straight Na channels (minor)
4.
What transports are taking place in the Thin descending limb?
No active transport occurs here. Reabsorption of water is the main thing that happens here, and is impermeable to most solutes. Epithelium is permeable to water and small ions.
What transporters are found on the thick ascending limb?
main one is Na/K/2Cl symporter. It’s impermeable to water. thus called the diluter.
What are some example of loop diuretics?
Furosemide, bumetanide
What is the permeability of DCT?
1 Permeability for water depends on ADH.
2. Permeability to electrolytes is very low = low conductance thus requires a HIGH electrochemical gradient to drive ion transport
What kind of transport (low/high conductance; high or low gradient) are you likely to find in the DCT?
Low conductance, high gradient. It uses a lot of energy (has more Na/K-ATPase than PCT) maintain a strong enough gradient to drive even more Na out of the tubular fluid.
What’s the main transporter at the DCT?
Na/Cl symporter
What does thiazide inhibit and where does it act?
Inhibits Na/Cl symporter and acts on the DCT.
In the TAL, what creates the gradient for Ca and Phosphate to get reabsorbed?
K being pushed out of the cell down it’s concentration gradient via the leaky K channels.
Where does final regulation of Na and water occur?
Late DCT.
Aldosterone works to increase Na reabsorption in principal cells by inserting what types of channels on the apical and basolateral sides?
Apical side: Na channels
Basolateral: Na/K ATPase
What parts of the nephron are principal cells found?
late DCT and CD
What are the functions of principal cells?
Na reabsorption, K secretion, water reabsorption
What are the functions of a-intercalated cells?
K reabsorption and H secretion
The permeability of water in both the DCT and Collecting tubules are dependent on _?
ADH
What are the three components of the countercurrent multiplier mechanism?
- Descending ascending limb
- Casa recta
- Collecting ducts
What happens to your ability to concentrate your urine with a high protein diet?
You are able to concnetrate your urine even further due to the breakdown products of protein being urine.
In the countercurrent multiplier mechnaism, what is the function of vasa recta?
Maintains solute gradient
WHat would happen to your urine concentration ability if you were given a drug that increase blood flow through the peritubular capillary?
The concentration ability of the kidney would decrease as the increased blood flow increase pressure.
What is obligatory urine volume?
The minimum amount of urine you have to excrete in order to eliminate the waste generated in the body during a day.
How do you calculate how much water is needed to eliminate the amount of waste produced?
About of waste produced divided by the total concentration. e.g 600 (daily waste) / 1200 (what the total concentration of urine/ intersitum is)
What is a major drawback for diuretics?
Diuretics decreases the body’s ability to concentrate urine to the max as dilute urine is excreted. Therefore the body has to excrete out larger volume of water to eliminiate all the waste produced.
