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blood urea nitrogen (BUN)
a blood test that measures the amount of urea nitrogen in the blood; elevated levels can indicate decreased renal function
Bowman’s capsule
part of the nephron that contains the glomerulus
cortical nephrons
comprise a majority of the functional units of the kidney located in the outer renal cortex
fenestrated capillaries
small blood vessels in the glomerulus that filter waste
glomerular filtration
initial step in making urine involving the filtering of excess fluid and waste products from blood
glomerular filtration rate (GFR)
the rate at which the kidneys filter the blood, calculated using the results of blood tests that measure renal function
located in nephrons, a tuft of capillaries surrounded by the Bowman’s capsule that filters blood
indentation on the medial side of the kidney that allows blood vessels, lymphatic vessels, and nerves to enter and exit
juxtamedullary nephrons
nephrons with longer loops of Henle that extend into the medulla
loop of Henle
part of the nephron that contributes to absorption of sodium
mesangial cells
cells that increase the body surface area for glomerular filtration by limiting the size of molecules that can be filtered
the process through which urine is released from the bladder
the functional units of the kidney that produce urine
renal colic
acute pain associated with kidney stones
renal cortex
outermost layer of the internal areas of the kidney containing nephrons
renal medulla
inner part of the kidney containing structures essential for regulating urine concentration
renal pelvis
funnel-shaped area of the kidney that collects urine and is connected to the ureter
tubular necrosis
damage to the tubule cells of the kidney typically resulting from reduced blood flow or chemical exposure
vasa recta
long, hairpin-shaped blood vessels that run parallel to the loops of Henle and facilitate water reabsorption
vesicoureteral reflux
abnormal backflow of urine from the bladder up through the ureters

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