Lecture 36 Unit 5

Question 1

by the end of DCT how much of solutes and water have been reabsorbed and returned to the blood stream

Answer 1

90-95%

Question 2

how does Na+ enter principal cells

Answer 2

through leakage channels

Question 3

what does aldosterone do to principal cells

Answer 3

increases Na+ and water reabsorption and K+ secretion by principal cells by stimulating the synthesis of new pumps and channels

Question 4

what does ADH do to principal cells

Answer 4

increases water permeability of principal cells in CD by triggering the insertion of aquaproin 2 channels into the apical membrane

Question 5

how is H+ secreted into tubular fluid via pumps

Answer 5

• can pump against H+ gradient 1000 times higher than blood

- urine is buffered by HPO4- and NH3 which combine irreversibly with H+ and carry away excess H+ ions

Question 6

how is bicarbonate absorbed via antiporters

Answer 6

• HCO3- is generated when carbonic acid dissociates
• Cl-/HCO3- antiporters exhange chloride in ISF for bicarbonate in intercalated cells
• HCO3- enters blood and pH rises

Question 7

what happens when blood becomes more acidic

Answer 7

1. form more carbonic acid fro CO2 and H20
2. secrete more H+ into tubular fluid
3. exchange more Cl- for HCO3-
4. thus more HCO3- enters blood pH

Question 8

what are diuretics

Answer 8

substances that slow renal reabsorption of water and cause diuresis

Question 9

what does caffeine do

Answer 9

inhibits Na+ reabsorption

Question 10

what does alcohol do

Answer 10

inhibits secretion of ADH

Question 11

what do some diuretic prescriptions do

Answer 11

act on pCT, loop of henle, or DCT

Question 12

how big is the urinary bladder

Answer 12

700-800 mL

Question 13

what is mictutrition

Answer 13

urination

Question 14

when do stretch receptors signal spinal cord and brain

Answer 14

when volume exceeds 200-400 mL