Name: ___________Haley Sommer____________________________________
1. Diuresis is the production and excretion of LOTS of urine. Anti-diuretic hormone therefore reduces the volume of urine.
a. If ADH reduces the volume of urine produced, what happens to the fluid that would have been excreted?
This causes the reabsorption of water in the distal arm and collecting duct because ADH inserts aquaporins into the collecting duct.
b. ADH is a protein hormone that acts on target cells through its receptor. What are the target cells within the vertebrate nephron?
The distal tubule and the collecting duct.
c. ADH acts to move aquaporins from an intracellular location in target cells to the plasma membrane. Aquaporins allow water to move into/out of nephron by osmosis (circle one). …show more content…
ADH is released from the posterior pituitary in response to either: 1) small increases in plasma osmolarity or 2) large drops in plasma volume. Considering the action of ADH on water reabsorption by the nephron, why would it make sense for these two kinds of stimuli to elicit ADH release. Think about this in terms of negative feedback!
An increase in osmolarity would call for an increase in water in order to maintain homeostasis; therefore, ADH would be released to reabsorb as much water as possible to maintain homeostasis. As for a drop in plasma volume, the same mechanism would occur. ADH would be released in order for water to be reabsorbed to increase plasma volume, because the blood would be a higher osmolarity with less