Kidney Function 2 - Osmoregulation

Question 1

what is osmoregulation?

Answer 1

-a homeostatic process that controls water balance in the body

Question 2

how is water balance controlled by osmoregulation in the body?

Answer 2

-it does this through controlling water balance in the blood, tissue fluid and cells

Question 3

where does water regulation occur?

Answer 3

-the collecting duct

Question 4

where is most water reabsorbed ?

Answer 4

-in the PCT and the descending limb of the loop of Henle

Question 5

is water reabsorption in the PCT and descending limb of the loop of Henle passive or active?

Answer 5

-passive as it moves according to concentration gradients

Question 6

how is water reabsorption controlled in the collecting ducts?

Answer 6

-by varying the permeability of the collecting duct walls

Question 7

what is the name of the hormone that helps vary wall permeability?

Answer 7

-ADH or antidiuretic hormone

Question 8

where is ADH produced and where is it released to and stored ?

Answer 8

-produced in the hypothalamus
-its then secreted into the posterior lobe and stored in the pituitary body

Question 9

what is the name of the specialized cells that monitor solute potential of the blood and are also produced in the hypothalamus?

Answer 9

-osmoreceptors

Question 10

what are 3 reasons why blood may become too concentrated?

Answer 10

-sweating after exercise/ hot day
-not drinking enough
-consuming too much salt

Question 11

what happens when blood becomes too concentrated, how is this fixed? (6 steps)

Answer 11

-osmoreceptors detect the blood being more negative
-more ADH is release form the pituitary body to the blood
-the walls of the DCT and collecting duct become more permeable
-more water is reabsorbed back into the blood
-solute potential returns to normal and a small volume of hypertonic urine is produced
-as the blood returns to normal negative feedback occurs and reduces the release of ADH

Question 12

what happens if blood is too dilute? (6 steps)

Answer 12

-blood becomes less concentrated which is detected by osmoreceptors
-less ADH released
-walls of DCT and collecting ducts become less permeable
-less water is reabsorbed
-large quantities of hypotonic urine produced
-negative feedback occurs when blood becomes too concentrated and then more ADH is released

Question 13

what are the names of the proteins that are in the walls of the collecting ducts that aid their permeability?

Answer 13

-aquaporins

Question 14

when is it most likely for blood to become too dilute?

Answer 14

-when drinking large amounts of hypotonic liquid