Urinary System Part 2 Flashcards
what is the juxtaglomerular apparatus
combined baroreceptor (pressure) and chemoreceptor ( [ion])
where is the JGA
specialized areas of afferent arteriole and DCT
what is the JGA used for
to regulate systemic blood pressure via renin angiotensin aldosteron system
what are the 3 components of the JGA
-macula dense
- juxtaglomerular cells
- extraglomerular mesangial cells
what is the macula dense
thickened region on one side of the DCT
what does the macula densa contain
densely packed cuboidal to columnar epithelial cells
what are the chemoreceptors in macula densa sensitive to
changes in [Na] filtrate
what are juxtaglomerular cells
modified smooth muscle cells in the wall of afferent arteriole
what do juxtaglomerular cells act as
baroreceptors, detect changes in BP
what do juxtaglomerular cells produce
renin in response to decreased blood pressure
what does renin do
converts angiotensin to angiotensin I
describe exrtaglomerular mesangial cells
flattened cells surrounding afferent and efferent arterioles
what is the function of extraglomerular cells
provide structural support and phagocytosis
- tubular glomerular feedback
how do extraglomerular cells assist in tubular glomerular feedback
by transmitting signals from cells of macula densa to glomerular mesangial cells
what happens with decreased blood pressure
- renin release from JG cells in afferent arteriole
- decrease GFR -> decreased Na in distal convoluted tubule
describe the renin angiotensin aldosterone pathway
renin causes angiotensinogen to be converted into angiotensin I. ACE in endothelial cells in lungs converts angiotensin I to angiotensin II
what does angiotensin II do
vasoconstrictor, increase in BP
where is angiotensinogen synthesized
liver
what are the 3 ways in which angiotensin II increases BP
- vasoconstriction
- release of aldosterone from zona glomerulosa of adrenal cortex -> resorption of Na and water from DCT
- ADH secretion from posterior pituitary -> increased water resorption from collecting tubule
what do ACE inhibitors do
prevent conversion of angiotensin I -> angiotensin II by blocking action of ACE, preventing BP increase
describe the ureters and their function
muscular tubes, conducting urine from kindeys to bladder
describe the lumen shape of the ureters
stellate or star shaped
what is the lumen of the ureter lined by
transitional epithelium
what are the 3 layers of smooth muscle of the muscularis externa in ureters
inner longitudinal and outer circular, third outermost longitudinal layer in lower third of ureter
how do ureters move urine
peristaltic contractions
what surrounds the ureter
fibroelastic adventitia of CT
what is the urinary bladder lined by
transitional epithelium with underlying fibroelastic lamina propria
what do the three openings of the urinary bladder define
trigone area
what are the openings in the trigone area
two for entry of urine from ureters and one for exit of urine via urethra
what is the urethra surrounded by
internal sphincter of smooth muscle
what are the three smooth muscle layers in the muscularis externa of the urinary bladder
inner longitudinal, outer circular, and outermost longitudinal interspersed with elastic fibers
what is the peritoneal or visceral surface of bladder covered by
fibroblastic adventitia called serosa
what does the urethra do
transfers urine from bladder to outside world
what epithelium lines the urethra
stratified or pseudostratified columnar epithelium with paraurethral mucus glands
what are the 3 sections of the urethra in males
prostatic, membranous, spongy (penile)
what is the prostatic urethra lined by
transitional epithelium
why are females more susceptible to bladder infections
short urethra
what is cystitis/ pyelonephritis
bacterial/fungal (yeast) infection
- rbc’s, wbc’s bacteria in urine, painful/burning urination
how is a bladder infection diagnosed
urine culture
what is another word for urination
micturition
what is proteinuria
excretion of protein in urine, usually albumin
what is glucosuria
excretion of glucose in the urine -> diabetes mellitus
what is polyuria
increased frequency of urination
what is polydipsia
increased frequency of drinking
what are polyuria and polydipsia both symptoms of
diabetes mellitus
what is polyuria and polydipsia caused by
ADH insufficiency -> high volume, dilute (hypotonic) urine
what might drugs or metabolites concentrated in urine precipitate as
crystals
what is nephrolithiasis/urolithiasis
crystal, stone formation -> urinary calculi
what are 80% of urinary stones made of
calcium oxalate
what are influential factors in urinary calculi
genetic and diet
where may urinary calculi lodge themselves
in renal pelvis , ureters, urethra
how are urinary calculi treated
ultrasound called ilithotripsy
what are the complications of urinary calculi
hydronephorosis and hydroureter, usually unilateral
what does BUN measure and indirectly measure
renal function; indirectly measures renal disease
when does BUN start to increase
when 75% of functional nephrons are lost -> uremia
