Kidney-ADH

Question 1

What does ADH stand for?

Answer 1

Anti-diuretic hormone

Question 2

What does ADH do?

Answer 2

Increased permeability of collecting duct walls so more H2O is reabsorbed into blood

Question 3

What is the first step in how ADH increases the permeability of collecting duct walls?

Answer 3

ADH is produced in the cell body of the neurosecretery cell

Question 4

What is the second step in how ADH increases the permeability of collecting duct walls?

Answer 4

ADH then diffuses along axon of neurosecretery cell

Question 5

What is the third step in how ADH increases the permeability of collecting duct walls?

Answer 5

ADH is stored in vesicles in terminal bulb

Question 6

What is the fourth step in how ADH increases the permeability of collecting duct walls?

Answer 6

If dehydrated, ψ of blood decreases so H2O leaves osmoreceptors by osmosis causing osmoreceptors to become flaccid/shrivel up

Question 7

What is the fifth step in how ADH increases the permeability of collecting duct walls?

Answer 7

An action potential is generated in the neurosecretry cell (from step 4) carrying ADH to be released by exocytosis

Question 8

What is the sixth step in how ADH increases the permeability of collecting duct walls?

Answer 8

ADH binds to receptors on epithelial cells/walls of collecting duct

Question 9

What is the seventh step in how ADH increases the permeability of collecting duct walls?

Answer 9

Step 6 causes vesicles containing aquaporins to insert aquaporins into ‘blood side’ of epithelial cell membranes which increases permeability of collecting duct to H2O

Question 10

What is the eighth step in how ADH increases the permeability of collecting duct walls?

Answer 10

More H2O can go to blood via osmosis so ψ of blood increases

Question 11

What happens after when ADH is lowered?

Answer 11

Aquaporins are removed by invagination and go back into vesicles