What happens when there’s a 1-2% increase in Na or a 10% decrease in blood volume?
osmoreceptors in the hypothalamus sense the change–> vasopressin secreted from posterior pituitary–> enhances H2O resorption in renal CDs
Na is a major determinant of intra or extracellular osmolality?
extra
incr in BP–> sensed by ______–> impulses to the ____ to inhibit ____ release and decrease ___ resorption in the distal nephron
incr in BP–> sensed by arterial and atrial baroreceptors–> impulses to the hypothalamus to inhibit vasopressin release and decrease Na resorption in the distal nephron
What happens when there is a decrease in BP to stimulate an increase in resorbed water in the kidneys?
decr in BP–> sensed by juxtaglomerular cells–> activate RAAS by secreting renin–> renin cleaves angiotensinogen to angiotensin I–> angiotensin I converted to angiotensinogen II by ACE–> angiotensinogen triggers release of aldosterone from the adrenals, secretion of vasopressin, and stimulates thirst
What are the actions of angiotensinogen II?
triggers release of aldosterone from the adrenals, secretion of vasopressin, and stimulates thirst
T or F: All hyperNa animals are hyperosmolar
T
What is the normal ECF osmolality?
300 mOsm/kg
What are effective osmoles?
osmoles that contribute to tonicity
What are examples of effective osmoles?
glucose, EG, propylene glycol
T or F: BUN is a strong effective osmole
F- BUN is an osmole but doesn’t cornice to tonicity b/c can freely diffuse across membranes
What is an example of a hypertonic rumens where BUN actually contributes to hypertonicity and is an effective osmole?
urea toxicosis
T or F: Hypoosmolar pts always have hypoNa.
T
T or F: HypoNa pts always are hypoosmolar.
F (if concurrent hyperglycemia)
What are 3 scenarios where you may have hyponatremia without a decrease in osmolality?
HypoNa in a normovol patient indicates…
increased total body Na
HypoNa in a dehydrated patient indicates…
Na and H2O are being lost together but Na loss is > H20; indicates severe total body Na deficit
HypoNa in a pt with ascites or edema indicates…
H2O is accumulating faster than Na can increase; tuna is normal to increased
HyperNa in a dehydrated pt indicates…
H2O loss w/o Na loss, tbNa is normal and ECF volume is decreased
HyperNa in a normovol pt indicates…
increase in tuna (usually excess salt w/o access to water)
What are 3 mechanisms of hypoNa?
What are 3 causes of renal Na loss leading to hypovolemic hypoNa?
What are 3 main causes of non-renal Na loss leading to hypovolemic hypoNa?
What are 4 causes of excessive water intake causing euvolemic hypoNa?
What are 4 causes of volume overload leading to hypervolemic hypoNa?