Physiology Flashcards
In trying to maintain the medullary osmotic gradient which would be most effective and why?
Increasing flow of the vasa recta, or decreasing flow of the vasa recta?
Decreasing flow of the vasa recta as this will allow more time for osmotic exchange increasing osmolarity deeper into the medulla.
ADH release is controlled by what hypothalamic neurons when osmolarity is high; when pressure at the baroreceptors has decreased?
osmolarity increase- supraoptic nuclei
pressure decrease- paraventricular nuclei
Both of these project axons into the posterior pituitary gland
ADH works through what membrane mechanism?
Gs protein and adenyate cyclase
Thirst is regulated by what?
Angiotensin II, and small increases in osmolarity
What are some potential problems with ADH function or delivery?
Central deficit in release
Nephrogenic deficit with non responsive kidneys
Transport deficit leading to breakdown of ADH
What is pressure naturesis and what does it protect against?
Pressure naturesis is an increase in renal artery pressure leading to a loss of sodium and water.
It can protect against continued aldosterone release; along with ANP.
Which hormone is the most effective player in long term control of sodium balance?
Aldosterone because it controls 2% of filtered sodium
Severe sweating triggers what type of responses?
Increase SNS, RAAS, ADH secretion
What is free water clearance?
Estimates the ability of the kidney to concentrate or dilute urine. Its produced by the TAL and early DCT
Whats the equation for free water clearance?
V-Cosm
Cosm is calculated like regular clearance (Ux * V)/Px
Positive value indicates solute free water excretion
i.e: Low ADH high water intake, Diabetes insipitus, nephrogenic diabetes
Negative value indicates solute free water absorption
Syndrome of inappropriate ADH secretion SIADH.
