renal function Flashcards
what urine:serum after ADH injection shows inadequate ADH secretion
3:1
- patient can respond if given ADH
how is RAAS initated
macula densa cells detect change in filtrate volume and sodium levels
how do macula densa cells communicate low sodium detected
connection to juxtaglomerular cells and cause those cells to release renin
what is the renin pathway
- renin
- angiotensin 1
- angiotensin 2
how does the RAAS system increase blood pressure
angiotensin 2 causes:
- vasoconstriction of efferent
- proximal tubule reabsorption of sodium
- aldosterone secretion and ADH secretion
what is the action of aldosterone
causes sodium reabsorption in distal convoluted tubule once released from adrenal cortex
what is the action of ADH
increases water retention by increases water permeability of distal tubules
define active transport
carrier proteins with electrochemical energy
define maximal reabsorptive capacity
the maximum reabsorption ability for a solute in the filtrate by the renal tubules
where does renal concentration begin
loops of henle driven by osmotic gradients and countercurrent mechanisms
what is unique about the ascending loop of henle
impervious to water
describe the countercurrent mechanism
veins run opposite flow direction as urine formation and collect salt from ascending loop due to low osmolarity and then water from descending
define tubular secretion
substance from blood (peritubular capillaries) to the filtrate (urine)
describe the purpose of tubular secretion
- elimination of waste products not filtered by glomerulus
- regulation of acid-base by secreting hydrogen ions
list 3 major mechanisms in kidney to maintain blood pH homeostasis
- excretion of H for bicarb
- excretion of H with phosphate
- excretion of H bound to ammonia to produce ammonium ion
