Urinary System Flashcards
What body fluid composition does the urinary system maintain?
water/ions
base/acid
How does the urinary system eliminate waste?
Cellular metabolism, phagocytosis, foreign chemicals, drugs and food additives
What minor endocrine function does the urinary system have?
secretes erythropoietin/renin to reg. bp
activates vitamin D which helps calcium absorption in SI
Urea
nitrogenous waste from protein; bulk of urine
Waste of muscle activities
Creatinine
Waste of nucleic acid
Uric acid
Hemoglobin breaks down and forms what waste?
bilirubin and other urochromes
PH in urine is…
variable/not constant 4.6-8
what could it mean if PH of urine is too high
infection or renal failure
what could is mean is PH of urine is too low
diabetes, mellitus, emphysema, starvation
what other systems help to remove waste besides urinary?
integumentary, respiratory and digestive
waste of respiratory
h2o and co2
waste of integumentary
nitrogen compounds, water and electrolytes (main function of sweat is temp regulation)
waste of digestive
digestive waste, bile pigments, heavy metal salts
what is urinary MOST important for?
water and electrolyte (ion) balance
What glands sit on top of kidneys
adrenal aka suprarenal
kidney location
retroperitoneal
urinary epithelium
transitional epi. or urothelium
traits of urothelium
impermeable to urine which is sterile but could be toxic, prevents water from being drawn into hypertonic urine, interdigitating cell junctions that make distension (stretching/expanding possible)
how many layers in ureters and names
3- mucosa, muscularis, adventitia
what does the mucosa layer consist of
transitional epi, lamina propria (connective tissue)
what does muscularis layer consist of
smooth muscle: inner-longitudinal, outer- circular (another longitudinal layer on outside in lower 1/3 of ureter)
what does the adventitia consist of
BV, lymphatics, nerves
what muscle is in bladder
detrusor muscle
how many mL will bladder hold until feel like peeing
300 mL (can be consciously overridden- holds 3X more)
two muscles at bottom of bladder that control urine being released and type of muscle
internal sphincter- smooth muscle- INVOLUNTARY
external sphincter- striated muscle- VOLUNTARY
orifice
opening
bladder layers
same as ureters except bladder has 3 muscular layers, same as bottom 1/3 ureter
position of urethra in female
anterior to vag opening, posterior to clit
3 regions of male urethra
prostatic, membranous, penile (spongy)
what does urethra secrete
mucous into urethral canal
micturition
voiding or urination
incontinence
loss of bladder control
general overview of how bladder expands (distension)
activation of stretch receptors trigger visceral reflex arch
how do efferent impulses get to bladder
pelvic splanchnic nerves (parasympathetic)
result of efferent impulses to bladder
detrusor contracts, internal sphincter relaxes (external can override)
what in kidney collect urine
calyces and pelvis
lobe in kidney
cortex capsule and pyramid
where is most urine produced
in nephrons in the cortex
What does each nephron consist of?
glomerulus, renal tubules (Bowman’s capsule, distal/proximal tubules, loop of Henle)
renal corpuscle
glomerulus + Bowman’s capsule
What do the thin walls of the glomerulus (capillaries) act as?
semi-permeable membrane
What is the filtrate from the glomerulus free of?
protein and RBC bc too big
Glomerulus mechanism
basically passive under some pressure
What may happen if you have very low blood pressure
the glomerular filtration stops, kidneys shut down
Where does reabsorption of filtrate take place
distal/proximal tubules
the two layers of Bowman’s capsule
outer: continuous with proximal part of renal tubule (simple squamous)
inner: podocytes- branching processes closely assoc. with glomerular capillaries; filtration slits btwn processes
spaces between pedicles
filtration slits
what should you never have in urine?
protein, glucose, or blood; indicates diabetes or kidney problems
part of glomerulus that means windows in german
fenestrae
glomerular hydrostatic pressure in glomerulus
hydrostatic= pushing up against BV from inside; PROMOTES outward flow/ encourages filtration
osmotic pressure of blood in glomerulus
opposes outward flow
Glomerular capsule fluid pressure
opposed outward flow
3 types of pressure involved in glomerular filtration and whether they oppose/promote outward flow
hydrostatic- promote
osmotic- oppose
glomerular capsid fluid- oppose
What pressure in the glomerulus wins
the hydrostatic, that’s how we filter the blood outward
pressure from the renal artery to the renal vein (decreases/increases)?
decreases
distal convoluted tubule in comparison to afferent arterial
they are leveled
where does filtrate in the efferent arterioles lead to in cortical nephron
to peritubule capillaries (adjacent to proximal and distal tubules), veins, interlobular, arcuate, interlobar, segmented, renal vein, vena cava, heart
where does the filtrate that goes through renal tubules go
into renal pyramids to ureters
vasa recta
in juxtamedullary nephrons, when filtrate leaves glomerulus via efferent arteriole it goes to peritubular capillaries then to these specialized veins that go around loop of henle (urine concentration) then to veins and back to heart
main purpose of glomerulus in nephron
produce protein free filtrate (2/3 gets reabsorbed)
main function of PCT and loop of henle
reabsorbs Na, K, and glucose by active transport, reabsorb Cl by diffusion, obligatory water reabsorption by osmosis, secretion of certain drugs by active transport (ex- penicillin)
when PCT and loop of henle “reabsorb” things like Na, what does this mean/where?
reabsorption out to the peritubular capillaries
when PCT and loop of henle “secrete” certain drugs what does this mean
secretion into tubules
main purpose of DCT
reabsorb Na by active transport, secrete H and K
main purpose of collecting tubules
reabsorb water by osmosis, ADH also controls reabsorption of water
how does DCT know if Na levels are too low?
macula densa
macula densa
sensitive to decreased concentration of Na (aka decreased bp)
juxtaglomerular cells
cuff of smooth muscle around afferent arteriole containing renin granules
juxtaglomerular apparatus
macula densa + juxtaglomerular cells
two situations renin will be released into bloodstream by juxtamedullary apparatus
if there’s a fall in systemic pressure or decreased Na bc where Na goes, water follows
what senses fall in systemic pressure in the juxtaglomerular apparatus
pressure receptor (juxtaglomerular cells) in wall of afferent arteriole
what sense decreased Na in juxtaglomerular apparatus
chemoreceptors (Macula Densa) in distal convoluted tubule
renin pathway
renin –> angiotensinogen (plasma protein) –> angiotensin I (polypeptide) –> angiotensin II (potent vasoconstrictor)
aldosterone
sodium retaining hormone released in adrenal cortex for vasoconstriction
how does aldosterone increase BP
promotes reabsorption of Na (water follows) expanding blood volume (pressure), made by hypothalamus released by pituitary
