Regulation of Body Fluid Osmolarity and Water Balance Flashcards
How would the vasa recta help to create concentrated urine?
Increased blood flow allows for the removal of salt from the medulary intersitium.
This will increase the gradient in the nephron, and allow for further absorption of the solutes.
Seems counter intuitive, but the increase in solutes will help drive water back in the collecting duct.
What channels contribute to “urea recycling”? Where are they located and what is the function?
UTA1 and UTA 3 are in the inner medullary collecting duct and allow for urea to be moved into the medullary interstitium.
UTA 2 is in the loop of Henle and increases movement of urea back into the nephron. (Simple diffusion occurs as well)
What neurons synthesize ADH?
The supraoptic and paraventricular nuclei of the hypothalamus.
What three major effects does ADH have?
Causes retention of water in kidneys
Suderiferous glands decrease water loss
Arterioles constrict, causing increased blood pressure
What can stimulate aldosterone release?
Released by adrenal cortex in response to angiotensin II, (low Na –> RAAS)
Rise in plasma K+
How can you treat Central “Neurogenic” Diabetes Insipidus?
Synthetic ADH, desmopressin
What receptor does desmopressin act on?
V2
What can cause Nephrogenic Diabetes Insidus?
Diuretics that inhibit electrolyte reabsorption in the loop of Henle
Lithum (manic depressive order treatement) or tetracyclin (antibiotics) can also cause impariement of the distal nephron in response to ADH
What disease can cause low sodium levels and water intoxication?
What are the symptoms of this disease?
SIADH
Lethargy, Abdominal cramps, excessive Thirst, Confusion, Hyponatremia. Exertion causing Dyspnea, Vomiting,
Latched V
What usually causes Hyponatreimia
ADH release in kidney is usual mechanism
Caused by:
Drugs
Decreased arteriol volume
Pain and Nausea
Strenous exercise
Note* rarely is it caused by lack of solute or polydipsea
What causes polyuria?
Diabetes mellitus, diabetes insipidus, excess caffeine or alcohol, kidney disease, certain drugs, sickle cell anemia, excessive water intake.
What are the mechanisms that cause polyuria
Increased intake of fluids
Increased GFR
Increased output of solutes
Inability to reabsorb water
What causes an increase in GFR?
Hyperthroidism
Fever
Hypermetabolic states
What diseases/drugs an increase in output of solutes?
Diabetes mellitus
Hyperthyroidism
Hyperparathyroidism
Use of diurectics
What causes solute/osmotic diureses?
Primary cause is salt intake increase
NaCl
Hyperglycemia
High protein intake
Recovery from acute kidney injury
