Control of water LEC 4 B7 Flashcards
Water is only reabsorbed where?
in descending limb of the loop of henle
Solutes are reabsorbed where?
in ascending limb of the loop of henle
makes interstium of medulla hyperosmotic
Active reabsorption occurs in the __________________.
Thick ascending limb
Hyperosmotic interstitium pulls water out of ________________.
Descending thick limb
-reabsorbs water and concentrates tubular fluid
_____________ blood flow is very slow, so as to not disturb the gradient.
Vasa recta
_____ is added back to the loop to further increase the concentration.
Urea
Urea is a waste product that we __________ when ADH is really high so we can reabsorb more water.
reabsorb
Know the formation of concentrated urine
Water deprivation… INcreases plasma osmolality, increases release of ADH
-Decrease BP, Decrease BV, Decrease RBF
Slow VASA RECTA flow allows for trapping of solutes in medulla
-Increase urea reabsorption
-Water reabsorbed
Know the formation of dilute urine
Water surplus… lowers plasma osmolality
Less ADH
Collecting ducts not permeable to water
water lost in urine
More vasa recta flow washes gradient out
(can happen with increased RBF)
Body water is sensed in 2 ways, what are they?
Baroreceptors:
-carotid bodies/aortic arch and atrial strectch receptors
-respond to BP changes
-less responsive
Osmoreceptors:
-Stretch sensitive cells in hypothalamus
-Respond to swelling and shrinking in ECF osmolarity
-Increase ECF Na+, Increase release of stored ADH
-More responsive
Osmoreceptors are more or less sensitive than baroreceptors?
more sensitive
Massive blood loss and too much sodium causes what?
Also being very dehydrated would cause this
Maximum ADH release
H
Minimal ADH release
Hypertension and Hyponatremia
Maximal ADH release
Hypotension and Hypernatremia
