Distal Convoluted Tubule (DCT), Collecting Duct and ADH Flashcards
(16 cards)
What increases these structures permeability to water?
ADH
What does ADH stand for?
Antidiuretic hormone
How does ADH increase permeability?
Attaches to receptors on the cells of the DCT and collecting duct
What does this stimulation lead to?
Aquaporins move to the cell surface membranes
What do aquaporins do?
Enable more water to be reabsorbed from these structures by osmosis down a water potential gradient
Where does this water go?
Passes into medullary tissue fluid and into blood capillaries leading to the renal vein
Where are osmoreceptors present?
Hypothalamus
What happens if there is a low water potential in the blood?
Osmoreceptors are stimulated
What happens after osmoreceptors are stimulated?
ADH travels down neurones to the posterior pituitary gland
Where does the ADH travel after the posterior pituitary gland?
ADH is released into the blood
What happens to the permeability of the distal tubule and collecting duct?
It increases
What happens to water in the blood?
More water is reabsorbed back into the blood
What is this process called?
Negative feedback
What happens if the water potential increases?
Stimulation of osmoreceptors is reduced
What does this mean for ADH in the blood?
It is lowered
What does this mean about water reabsorbed into the blood?
Less water is reabsorbed - so more water in the urine
