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36 terms

Urinary System

STUDY
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kidneys
retroperitoneal
cortex
outer layer of kidney skin substance
medulla
inner portion of kidney
pyramids
triangular divisions of medulla
papilla
narrow, innermost end of pyramid
pelvis
expansion of upper end of ureter; lies inside kidney
calyces
cup-shaped division of renal pelvis
nephrons
consist of renal corpuscle and renal tubule
renal corpuscle
bowman's capsule and glomerulus
bowman's capsule
the cup-shaped top
glomerulus
network of blood capillaries surrounded by bowman's capsule
renal tubule
proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting tubule
function of kidneys
excretes toxins and nitrogenous wastes; regulates levels of many chemicals in blood; maintains water balance; helps regulate blood pressure via secretion of renin
two main regions of kidney
cortex and medulla
formation of urine
filtration, reabsorption, secretion
filtration
goes on continually in renal corpuscles; glomerular blood pressure causes water and dissolved substances to filter out of glomeruli into bowman's capsulse; normal glomerular filtration rate is 125 ml per minute
reabsorption
movement of substances out of renal tubules into blood in periteubular capillaries; water, nutrients, and ions are reabsorbed by osmosis from proximal convoluted tubules
secretion
movement of substances into urine in the distal and collecting tubules from bood in peritubular capillaries; hydrogen ions, potassium ions, and certain drugs are secreted by active transport; ammonia is secreted by diffusion
control of urine volume
mainly by the posterior pituitary hormone's ADH, which decreases it
ADH
decreases urine output
aldosterone
increases urine output
ureters (structure)
narrow long tubes with expanded upper end located inside kidney and lined with mucous membrane
ureters (function)
drain urine from renal pelvis to urinary bladder
urinary bladder (structure)
elastic muscular organ, capable of great expansion; lined with mucous membrane arranged in rugae, like stomach mucosa
urinary bladder (function)
storage of urine before voiding, voiding
urethra (structure)
narrow tube from urinary bladder to exterior; lined with mucous membrane; opening of urethra to the exterior called urinary meatus
urethra (function)
passage of urine from bladder to exterior of the body; passage of male reproductive fluid from the body
micturition
passage of urine from body, AKA urination and voiding
internal urethral sphincter
involuntary regulatory sphincter
external urethral sphincter
voluntary regulatory sphincter
emptying reflex
initiated by stretch reflex in bladder wall; bladder wall contracts; internal sphincter relaxes, external sphincter relaxes and urination occurs
urinary retention
urine produced but not voided
urinary suppression
no urine produced but bladder is normal
incontinence
urine voided involuntarily; may be caused by spinal injury or stroke; retention of urine may cause cystitis
cystitis
bladder infection
overactive bladder
called interstitial cystitis; amounts voided are small; extreme urgency and pain are common