39 terms

Unit 15 The Urinary System

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buffer
chemical substance or system that minimizes changes in ph by releasing or binding hydrogen ions.
acidosis
state of abnormally high hydrogen ion concentration in the extracellular fluid.
renin
substance released by the kidneys that is involved with raising blood pressure.
glomerular capsule
double-walled cup at end of a renal tubule; encloses a glomerulus. also called bowman's capsule.
hilus
the indented region of an organ from which blood and/or lymph vessels and nerves enter and exit.
base
a substance capable of binding with hydrogen ions; a proton acceptor.
filtration
passage of a solvent and dissolved substances through a membrane or filter.
glomerulus
cluster of capillaries forming part of the nephron; forms filtrate.
renal calculus
a kidney stone.
urinary system
system primarily responsible for water, electrolyte, and acid-base balance and removal of nitrogenous wastes.
excretion
elimination of waste products from the body.
micturition
urination, or voiding; emptying the bladder.
urethra
canal through which urine passes from the bladder to outside the body.
urea
main nitrogen-containing waste excreted in urine.
ureter
tube that carries urine from kidney to bladder.
renal pyramids
triangular-shaped areas of tissue in the medulla of the kidney
retroperitoneal
located behind the peritoneum of the abdominal cavity
aldosterone
"salt-retaining hormone" which promotes the retention of Na+ by the kidneys. na+ retention promotes water retention, which promotes a higher blood volume and pressure
transitional epithelium
combination cuboidal and columnar, stretch readily and permit distenstion by urine, found in ureters, bladder, and part of urethra
uric acid
an insoluble precipitate of nitrogenous waste; may accumulate in joints - gout
hypothalamus
a neural structure lying below the thalamus; directs eating, drinking, body temperature; helps govern the endocrine system via the pituitary gland, and is linked to emotion
trigone
triangular area in the urinary bladder in which the ureters enter and the urethra exits
renal columns
extensions of cortical tissue that dip down into the medulla of the kidney between the renal pyramids
atrial natriuretic peptide
hormone secreted by the heart when there is an increase in blood flow which increases sodium excretion, and lowers blood pressure
alkalosis
A disorder in which the blood becomes basic; pH greater than 7.45
antidiuretic hormone (ADH)
hormone produced by the neurosecretory cells in the hypothalamus that stimulates water reabsorption from kidney tubule cells into the blood and vasoconstriction of arterioles; increases BP and lowers urine output
bicarbonate buffer system
a buffer in blood
creatinine
nitrogenous waste by product of muscle metabolism
glomerular filtration
pressure induced movement of material from the blood into the filtrate
juxtamedullary nephrons
nephrons with well-developed loops of Henle that extend deeply into the renal medulla
loop of Henle
section of the nephron tubule that conserves water and minimizes the volume of urine
nephrons
functional units of the kidney; approximately 1 million per kidney
peritubular capillaries
network of capillaries that surrounds the proximal and distal tubules in the kidney
renin-angiotensin mechanism
major control of blood pressure; involves the release of aldosterone and vasoconstriction
tubular reabsorption
movement of material from the renal tubule (filtrate) back to the blood
tubular secretion
movement of material from the blood in the peritubular capillary into the renal tubule (filtrate)
urinary bladder
muscular sac, lined with transitional epithelium, that stores urine
urine
fluid produced by the kidneys that contains water, urea and other waste materials
countercurrent exchange
the opposite flow of adjacent fluids that maximizes transfer rates; for example, blood in peritubular capillaries and the fluid in the nephron loop