Azotemia

hypersthenuria

excretion of urine of high specific gravity and concentration of solutes resulting usually from loss of water.

Afferent vasodilation

increase GFR

Efferent constriction

increase GFR

hyposthenuria

secretion of urine of low specific gravity due to inability of kidney to concentrate urine normally.

Afferent constriction

Decrease GFR

Renal azotemia

Due to a decreased GFR when more than 3/4 of the nephrons are nonfunctional.

Prerenal azotemia

Due to decrease in GFR from circulatory disturbances and decreased renal blood flow not from renal failure.

Increase in BP

Increase in GFR

Post-renal azotemia

Results from an obstruction or rupture of urinary outflow tracts.

Azotemia

an accumulation of nitrogenous waste products, such as blood urea nitrogen (BUN) and creatinine.

isosthenuria

the excretion of urine having the same specific gravity (and osmolality) as the plasma. Because the specific gravity of protein-free plasma and the original ultrafiltrate is 1.010, the inability to excrete urine with a higher or lower specific gravity indicates significantly impaired renal tubular function, -inability of the kidney to concentrate or dilute the urine The CONCENTRATING ABILITY of the kidney is impaired mainly because (1) the rapid flow of tubular fluid through the collecting ducts prevents adequate water reabsorption (2) the rapid flow through both the loop of Henle and the collecting ducts prevents the countercurrent mechanism from operating effectively to concentrate the medullary interstitial fluid solutes. as progressively more nephrons are destroyed, the maximum concentrating ability of the kidney declines and urine osmolarity and specific gravity (a measure of the total solute concentration) approach the osmolarity and specific gravity of the glomerular filtrate.