Reabsorption of ADH Flashcards
how does the brain sensing that there is not enough water in the blood affect ADH
- brain senses not enough water in the blood
- pituitary gland secretes more ADH
- ADH causes the kidneys to reabsorb more water, as collecting duct increases permeability
- causing you to absorb more water and not pee it out
how does the brain sensing that there is too much water in the blood affect ADH
- brain senses too much water in blood
- pituitary gland secretes less ADH
- makes kidneys reabsorb less water, as collecting duct decreases permability
- causing you to pee out water
what does the amount of water reabsorbed into the bloodstream depend on
the hormone ADH
what does an increase in ADH result in
less urine and higher concentration of it
what does a decrease in ADH result in
more urine and a lower concentration of it
what occurs in the proximal convoluted tubule
reabsorption of 99% of filtrate (all glucose and mineral ions)
if glucose and ions are reabsorbed against the concentration gradient in the proximal convoluted tubule, what does it mean in terms of the characteristics of the tube
as absorbing something against the concentration gradient requires energy (active transport), it has mitochondria in the cells of the tube
what occurs in the loop of henle
water is reabsorbed by osmosis
what occurs in the distal convoluted tubule
mineral ions are reabsorbed into blood by active transport
what occurs in the last part of the nephron (collecting duct)
water is reaborbed by osmosis again, but how much water being reabsorbed depends on ADH
what are the 3 sub parts of the last part of the collecting duct
cortex, outer medulla and inner medulla
how is the nephron adapted to for the reabsorption of substances
- large surface area of contact between nephron and capillaries
- cell membrane of cells lining the first convoluted tubule have tiny folds called microvilli, which increase surface area of cells
- cells that have protein pumps in their cell membranes contain many mitochondria
