Urinary System Flashcards
parts of the urinary system
kidney, bladder, 2 ureters, uretha
kidneys
homeostatic organs
kidney function
filter and maintain body fluids, retain improtant molecules and remove wastes, excess ions, regulate pH, fluid volume and salts
endocrine function of kidneys
renin and erythopoeitin
anatomy of kidney
bean shaped, size of a bar of soap, retoperioneal
hilus of kindey
vertical cleft, entry site for blood vessels, lymphatics, nerves
renal capsule
strong barrier
adipose capsule
fatty mass that cushions kidneys
renal fascia
dense fibrous CT, anchors kidneys
inside of kidney
cortex, medulla, lobe, pelvis, calyces
renal cortex
outer granular tissue
renal medulla
reddish brown pyramids
renal columns
cortical tissue between pyramids
lobe of kideny
each pyramid and surrounding tissue, approx. 8
renal pelvis
funnelshaped tube continous with ureter at hilus, branches in to major then minor calyces
calyces
collect urine, propelled by peristasis of calyces, pelvis and ureter
renal artery
deliver 25% of total cardiac output/min
nerve network of kidney
controlled by sym. fibers
steps of blood flow to the kidney
aorta-renal-segmental artery-interlobular artert-arcuate artery-cortical radiate artery- afferent arterole- glomerulus
steps of blood flow out of kidney
glomerulus-efferent arterole-capillaries-cortical radiate vein-arcuate vein-interlobular-renal-IVC
nephrons
1 million per kidney, form urine, several connect up to 1 connecting duct
what does a nephron consist of
a glomerulus, renal tubule, glomerular capsule, renal corpsulcle
renal corpsulce
glomerulus and glomerular capsule
epithelium of glomerulus
fenestrated, allows large volumes of fluid to filter from blood into glomerular cpaulse
what is the filtrate in golmerulus?
unprocessed urine
endothelium of glomerular capsule
outer parietal, visceral lal=yer
outer parietal layer
simple squamous epithelium
inner visceral layer
podocytes
podocytes
octupus-like with extensions called pedicles
proximal convoluted tube
region, cuboidal, actively reabosrb solute, secrete molecues
loop of henle thin segment
simple squamous, freely permeable to H2O
loop of henle thick segment
cuboidal, secrete solutes into filtrate
distal convulted tube
coiled region connects to collecting ducts, cuboidal cells, secrete solutes
cortical nephrons
85%, high in cortex, except fo tip of the loop of henle
duxtamedullary nephrons
located closer to medulla, low in cortex, loop goes deep in medulla (long)
role of duxta nephrons
concentrate urine
afferent arterioles
arise from interlobular arteries, feed the glomerulus
b.p of afferent arterioles
55 mmHg, easily forces fluid and solutes out of glomerulus
efferent arterioles
drain the glomerulus
peritubular capillaries
arise from efferent arteriles draining glomeruli, cling to renal tubules
function of peritubular capillaries
absorption of solute and water
glomerulus function
produce filtrate
juxtaglomerulus apparatus location
portion of distal tubule nestled between afferent and efferent arterioles
where are the JG cells located
in the walls of arterioles
function of JG cells
sense b.p in afferent arteriole, change efferent arteriole
GFR
glomecular filtration, 120 mls/min
if BP increases the glomerular
may rupture bv, filtration has a lot of water, flows quickly and cuboidal cells have no time to pull anything out
if bp decreases, the glomerular
kindeys do not do their job, filtration prduction decreases, cells pull too much out
process of renin in jg cells that increase GFR
activates angiotensin 1, ace activates angiotensin 2 which acts as a vasoconstrictor of efferent aretioles and release of aldosterone
macula densa cells
columar cells in distal tubule
what do MD cells do
sense filtrate flow, release ATP to vasocinstrict, affect afferent arteriole
urine
waste and excess substances
unporcessed filtrate
like plasma, but not proteins
process of urine formation
glomerular filtration
tubular reabsorption
secretion
what is urine formation regulated by
renal and hormonal controls
glomerular filtration
passive, high pressure, produces 180 L/day
forces that increase glomerular filtration
hyrdostatic pressure
forces that decrease glomerular filtration
osomotoic pressure, hydrostatic pressure in glom. capsule
what is the over all filtration pressure
10 mmHg
how much of a drop in pressure stops filtration
15%
osmotic pressure
30
regulation of glomerular filtration
autoregulation and renin
autoregulation
myogenic and tubuioglomerular feedback
myogenic regulation
fastest, reflex mechanism, smooth muscle contracts when stretched
for myogenic if bp goes up
vessels stretch-vasoconstriction-decrease flow and maintain GFR
for myogenic if bp does down
decreased blood flow-decrease stretch of vessels-vasodialation-increase flow and maintain GFR
tubuloglomerular feedback
macula densa cells detect and filtrate flow and osmotic levels
low flow or osmolarity for tublo feedback
MD cells do not release ATP-vasodialation of afferent arteriole-more blood enters glomerulus-GFR increases
high flow or osmolarity for tublo feedbacl
MD cells release ATP-vasoconstriction of afferent- less blood enters glomerulus- decrease GFR
renin angiotensin mechanism
vasocronstriction of arterioles increase GFR, aldosterone lowers osmolarity
Sympatheric nervous system
regulates renal flow during exterme stress, vasoconstriction, shunts blood to vital organs, reduces fluid loss
concentration of blood
280-300 mom
tubular reabsorption
takes place in the PCT
steps of tubular reabsorption
1-basolateral membrane, 3 NA is pumped into intersitial space by Na/K pump, atp is used
2- Na enters PT cell from tubule due to facilitaed diffusion and Na conc. gradient
3- passengers during secondary active diffusion: glucose, aa, ions, vitamins
4- reaborpstion of water by osmosis
5-lipid soluble substances by transcellualr
6- cl, ca, k and urea diffuse by paracellular route
concurrent multiplier
in loop of henle, makes interstital fluid salty
descending limb of henle
water leaves
ascedning limb of henle
solutes can leave
bottom of loop conc.
1200, in medulla
fluid conc. entering loop
300, in medulla
fluid conc. leaving loop
100
what causes water to leave desceding loop?
high osmolarity of intersitial fluid
from Na exiting
urea exiitng lower duct
aldosterone
collecting duct
monitors extracellular space
concentrating urine
millisomoles, kidneys regulate concentration of urine
vasa recta
highy permeabe to water and solutes, helps maintain osmotic gradient
descending limb of vasa recta
water leaves, salt enters (300)
ascending limb of vasa recta
water enters, salt leaves, 325