10.4 Glossary

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

glomerulus

located in nephrons, a tuft of capillaries surrounded by the Bowman’s capsule that filters blood

hilum

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

micturition

the process through which urine is released from the bladder

nephrons

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

From Chapter 34

OpenStax

acute kidney injury (AKI)

a decrease in kidney function that has an abrupt onset and is possibly reversible, manifested by decreased urine output and/or increased serum creatinine; previously known as acute renal failure

ascites

abnormal fluid present between the peritoneum and the abdominal organs

chronic renal disease (CRD)

a state of progressive decline of kidney function from a glomerular filtration rate of 59 mL/minute/1.73 m² to a glomerular filtration rate of less than 15 mL/minute/1.73 m²

diuretic braking

a progressive decrease in urinary output after repeated doses of loop diuretics

diuretic resistance

the state in which the maximum dose of a loop diuretic fails to produce the anticipated effect on fluid volume status because successive doses of the drug trigger hypertrophy of the distal tubule, increasing sodium reabsorption

end-stage renal disease (ESRD)

the condition that exists when the glomerular filtration rate falls below 15 mL/minute/1.73 m²

glomerular filtration rate

the rate at which the kidneys filter blood; indicates kidney function

hyperkalemia

serum potassium level greater than 5.2 mEq/L

hypernatremia

serum sodium level greater than 145 mEq/L

hypervolemia

body fluid overload, which includes excess fluid volume and edema

hypokalemia

serum potassium level less than 3.5 mEq/L

hyponatremia

serum sodium level less than 135 mEq/L

hypovolemia

decreased extracellular fluid volume associated with sodium and water loss

loop diuretics

drugs that interrupt the reabsorption of sodium and water in the loop of Henle, resulting in increased urinary output

nephrotic syndrome

a group of renal alterations that result in abnormal renal excretion of large amounts of protein

nocturia

the need to frequently void during the night, interrupting sleep

osmotic diuretics

drugs that draw fluid from the cells by increasing osmotic pressure

ototoxicity

temporary or permanent damage to the inner ear due to drug therapy

potassium-sparing diuretics

drugs that interrupt sodium and water reabsorption while retaining potassium and increasing urinary output

sodium–potassium–chloride cotransporter (Na-K-2Cl or NKCC2)

a protein that facilitates transport of sodium, potassium, and chloride into cells

thiazide and thiazide-like diuretics

drugs that increase urinary output by reabsorbing sodium and retaining potassium in the nephron