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urinary system chapter 24
Terms in this set (19)
Urinary tract: ureters, urinary bladder, and
kidneys, blood vessels
The kidneys filter waste products from the bloodstream and
convert the filtrate into urine.
Regulates the volume, composition and pH of body fluids, adjusts
water loss, releases of EPO and renin
Removes excess water, electrolytes and other wastes (urea, urine)
Storage of urine and excretion of urine
Regulation of erythrocyte production.
As the kidneys filter the blood, they are also indirectly measuring
the oxygen level in the blood
Located on either side of vertebral column, left slightly superior,
Reddish brown color, bean shaped with smooth surface.
Tough renal capsule (fibrous)
Hilus: depression, vessels & nerves enter/exit
Cortex: under capsule, location of glomerular capsules
Medulla: renal pyramids, papilla, columns
Renal Sinus: minor calyx, major calyx, renal pelvis to ureter
kidney blood supply
Arteries: renal artery >segmental> interlobar >arcuate >interlobular > afferent arterioles >glomerulus >efferent arterioles >capillaries
Veins: from capillaries >interlobular arcuate >interlobar >renal vein
Capillaries: peritubular (cortex) or vasa recta (medulla)
The functional filtration unit in the kidney.
Kidneys house approx 2.5 million nephrons.
Filtration is mostly a passive process based on solute size and conc. gradients
Blood to be filtered arrives at the nephron via the glomerulus (capillary)
Types: Cortical or Juxtamedullary
renal corpuscle (Bowman's or
glomerular capsule w/glomerulus)
proximal convoluted tubule
distal convoluted tubule
renal tubule: PCT, loop of
proximal convoluted tubule
Actively reabsorb almost all nutrients (glucose, a.a.,f.a.), electrolytes, and any plasma proteins.
Approximately 60% to 65% of the water in the tubular fluid is reabsorbed by osmosis.
The solutes and water are returned to the blood via the peritubular capillaries or vasa recta
Begins at the PCT, extends into the medulla.
Each loop has two limbs:
descending limb: reabsorbs water from surrounding tissue
ascending limb: Na+ and Cl- are released to the surrounding tissue
As solute conc. of interstitial fluid increases due to ascending limb release a conc. gradient is produced that pulls water out of the descending limb.
Thin portions of both limbs are permeable to water.
distal convoluted tubule
Begins at the end of the nephron loop.
Impermeable to solutes, must use active transport to pass ions (pumps regulated by aldosterone)
Reabsorption of water occurs here under the influence of two hormones:
Aldosterone: increase DCT absorption of
Na+ and water, increase loss of K+,
secreted by adrenal gland
Antidiuretic hormone (ADH):reabsorption
of water, increase blood volume at the
kidney, secreted by post. pit.
collecting tubules and ducts
If an individual is well hydrated, the collecting ducts simply transport the tubular fluid into the calyxes >pelvis >ureters
However, if an individual is dehydrated, water conservation must occur, and more-concentrated urine is produced.
ADH may act on the collecting duct epithelium,making it more permeable to water from the tubular fluid.
Long, fibromuscular tubes
that conduct urine to the bladder. Each tube averages 25 cm in length and is
The ureters originate at the renal pelvis and exits the hilum of the kidney.
Three tunics: mucosa, muscularis, and adventitia.
Peristaltic contractions are used to move urine to bladder.
Expandable, muscular sac, reservoir for urine. Positioned immediately superior and posterior to the pubic symphysis.
Females: contacts the uterus posterosuperiorly and with the vagina posteroinferiorly.
Males: contacts the rectum posterosuperiorly and is immediately superior to the prostate gland.
immovable portion of the urinary bladder.
Fibromuscular tube that exits the urinary bladder and conducts urine to the exterior of the body.
The lining is a protective mucous membrane that houses mucin-producing cells.
Bundles of smooth muscle fibers surround the mucosa and help propel urine to the outside of the body.
restrict the release of urine
until the pressure within the urinary bladder is high enough and voluntary activities needed to release the urine are activated.
Internal urethral sphincter (smooth, involuntary) surrounding the neck of the bladder, where the urethra originates.
External urethral sphincter (skeletal, voluntary-SNS) is in the urogenital diaphragm
Urinary and reproductive functions, passageway for both urine and semen
Approximately 18 to 20 cm long.
Partitioned into three segments:
prostatic urethra is approx. 3 to 4 cm long, extends through the prostate gland, immediately inferior to the male bladder
membranous urethra extends from the inferior surface of the prostate gland through the urogenital diaphragm
spongy urethra encased within a cylinder of erectile tissue in the penis (corpus
The expulsion of urine from the bladder.
Micturition reflex: complex sequence of events starting with stretch receptors in the bladder wall.
The bladder is supplied by both parasympathetic and sympathetic nerve fibers
When adequate stretch stim. is present, parasympathetic motor neurons stim. muscles of the bladder to contract.
Elevates pressure of fluids in the bladder, urine release only occurs when both the urethral sphincters relax
If external sphincter doesn't relax then no urine is expelled and bladder relaxes.
When more urine arrives, the stim. repeats, but is stronger this time.
Tensing of the abdominal and expiratory muscles increases pressure and assists in compressing the bladder... pee faster, but be careful!
outer layer of the kidney
Type of nephron that loops reach deep into the medulla
THIS SET IS OFTEN IN FOLDERS WITH...
general and special senses
endocrine system chapter 17
reproductive system chap 28
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