Kidneys controlling blood water potential Flashcards
Where is water absorbed
PCT, loop of henle, DCT and colllecting duct
What does Loop of henle do
Located in medulla , responsible for water being reasborbed by collecting duct there by concentrating urine so has low water potential.
How does the Loop of Henle maintain Na ion gradient
Two limbs ascending (impermeable) and descending (permeable). Na actively transported out of ascending using ATP into medulla creating lower water potential as high ions in medulla. Water moves from descending into medulla by osmosis as low water potential in medulla. Base of ascending Na diffuse out of filtrate lowering water potential. Water moves out of DCT and absorbed in blood , water continuous move out in collecting duct via osmosis. Water passes through aquaporins ADH control number of these channels.
How do osmoreceptors work
When water potential low water moves out off osmorecptor so it shrinks this sends signal to hypathalumus sending signal to pituitry gland to secrete ADH. ADH makes wall of DCT more permeable to water
