Urinary System I & II Flashcards
What two hormones does the kidney produce? What do they do?
erythropoietin - stimulated RBC production
Renin - influences blood pressure and the concentration of Na in body fluids
the renal hilum is continuous with what structure?
renal sinus (central cavity containing fat)
what is at the apex of each renal pyramid?
renal papilla with its perforated tip called the area cribrosa
where does the area cribosa project?
into the lumen of the minor calyx
what is a medullary ray?
group of straight tubules that project into cortex from the base of each renal pyramid
what makes up a renal lobe?
cotical tissue - medulla - cortical tissue
what makes up a renal lobule?
medullary ray (center) and surrounding cortical tissue
what are all nephrons in a single lobule drained by?
the same collecting tubules
what makes up the uriniferous tubule?
nephron
collecting tubule
- originate from different embryologic structures
what are the two types of nephrons? What is their distinguishing features?
cortical - short loops of Henle
juxtamedullary - long loops of Henle (help kidneys form hypertonic urine)
- depends on location of the renal corpuscle
what makes up the renal corpuscle?
glomerulus (capillary tuft)
Bowman’s capsule
what kind of epithelium make up the parietal layer of Bowman’s capsule?
simple squamous epithelium
what type of epithelium makes up the visceral layer of Bowman’s capsule?
modified simple squamous epithelial layer investing the glomerular capillaries
what cells are found in the visceral layer of Bowman’s capsule?
podocytes
what are podocytes?
modified simple squamous epithelial cells that make up the visceral layer (glomerular epithelium)
stellate shaped
have radiating processes - give rise to pedicles = foot processes
pedicles interdigitate with neighboring podocytes pedicles
what is found between adjacent pedicle filtration slits?
bridge of slit diaphragm (membrane)
where is the basal lamina located in the glomerulus?
between the podocytes and the endothelial cells in glomerulus
what are the 3 zones of the basal lamina in glomerulus?
lamina rara externa
lamina rara interna
lamina densa
what are characteristics of the endothelium?
thin and fenestrated lining capillaries = huge holes!
no diaphragms
contains most organelles in thicker regions
what is the function of the filtration barrier? Where is it located?
functions to filter blood plasma
located in renal corpuscle
what does the filtration barrier allow to enter capsular space?
water
ions
small molecules
what defines what can pass through filtration barrier?
size, shape and charge of molecules - absolutely cannot be negative because everything else is negative!
where are interglomerular mesangial cells found? What is their function?
interstitial space of glomerulus between capillaries
clean up basal lamina
why do interglomerular mesangial cells contract?
to decrease surface area available for filtration
what do interglomerular mesangial cells have receptors for?
angiotensin II
atrial naturitic factor
what is a feature of proximal convoluted tubule? what is its function of its apical and lateral borders?
well developed brush border = Mv
apical - protein absorption
lateral - water absorption
extensive basal plasma infoldings - ionic exchange!
where are 80% of NaCl and water and ALL the glucose, amino acids, and small proteins in glomerular filtrate absorbed?
proximal convoluted tubule
in the PCT, what are H+ secreted in exchange for?
bicarb
Note - acids and bases also secreted here
where is the first place we see transitional epithelium?
minor calyx
whats another name for medullary rays?
pars recta
why is the renal cortex granular?
renal corpuscle
what marks the boundary between cortex and medulla?
arcuate a.
what are the two parts of the cortex?
pars recta
pars convoluta
what makes up the pars convolute?
renal corpuscle
convoluted porteion of the distal and proximal tubules
corticocollecting duct
what is the parenchyma of the urinary system and where is it located?
uriniferous tubule
renal lobule
define renal lobule?
going from one interlobular blood vessel to the next interlobular blood vessel
what hemisects pars convoluta?
interlobular a.
what marks the beginning of the DCT?
macula densa
what type of capillaries do cortical nephrons have?
peritubular
what type of capillaries do juxtamedullary nephrons have?
vasa recta
where do peritubular and vaca recta capillaries come off?
efferent arterioles
where do podocytes sit?
in urinary space
what happens if intraglomerular mesangial cells do not work?
membranous nephritis
what happens is there is no diaphragm present across slits?
nephritis
what is it called when the pedicles are laying down and not doing their job (80% of kids)?
adolescence nephritis
what organ has the largest basement membrane?
kidney
what are characteristics of the descending pars recta (straight portion) of the proximal tubule?
lined by simple cuboidal epithelium
prominent brush border
cells are shorter that PCT
region is often damaged in acute renal failure and mercury poisoning
initial part of thick descending limb of the loop of Henle
what kind of epithelium does the thin limb of the loop of Henle have?
simple squamous - buldging nucleus into lumen!
what type of epithelium makes up the thick limb of the loop of Henle?
simple cuboidal epithelium
nuclei in apical position
impermeable to water
what are features of the DCT?
begins at macula densa
mv short
nuclei in apical portion
osmoregulator
what is the macula densa?
in DCT near afferent glomerular arteriole
one compartment of the juxtaglomerular apparatus
what are the cells like in macula densa?
tall
narrow
lined up closely
= forms a dense spot
where is the juxtaglomerular apparatus located?
vascular pole fo renal corpuscle
what makes up the juxtaglomerular apparatus?
modified smooth muscle cells of affront arteriole
efferent arteriole
macula densa
extraglomerular mesangial cells
what is the function of the juxtaglomerular apparatus?
JG cells release renin in response to decreased EC fluid
what does renin act on?
angiotensinogen in plasma - converting it to angiotensin I
what converts angiotensin I to angiotensin II?
capillaries in lungs
what does angiotensin II do?
cause a release of aldosterone from the z. glomerulosa cells in adrenal cortex
potent vasoconstrictor, elevates BP
what does aldosterone do?
stimulates Distal tubule cells to retain Na - water follows Na
what do collecting tubules in the cortex and medulla response to?
ADH = vasopressin
what is the role of the collecting tubules in the medulla?
primary role in producing a concentrated urine (est. a gradient due to the transport fo urea form the tubular fluid into the renal interstitum)
what are the two types of cells found int he cortical collecting tubules?
Light cells - principle
dark cells - intercalated
what is the set up of medullary collecting tubules?
similar to cortical collecting tubules
dark cells present in outer medulla
dark cells absent in inner medulla
principle cells increase in height - only cell lining the collecting tubule in inner medulla!
how are the papillary collecting tubules (duct of Bellini) formed?
converging collecting tubules
what type of epithelium does the papillary collecting tubules (duct of Bellini) have?
simple columnar
only principal cells
where does the papillary collecting tubules (duct of Bellini) empty?
area cribosa on the apex on renal papilla!
what are the two cells types of renal interstitial?
fibroblasts
mononuclear cells
have cells that decrease BP
what is found in upper 2/3 of ureter?
inner longitudinal
outer circular
what is found in lower 1/3 of ureter?
additional outer longitudinal later
what is scalloped in relaxed state?
urinary bladder lumen
what are the muscularis layers in the urinary bladder?
inner longitudinal
middle circular
outer longitudinal
what type of epithelium lines the prostatic portion of the male urethra?
transitional
what type of epithelium lines the remaining poritions of the male urethra?
pseudostratified or stratifed columnar epithelium
where are mucus secreting glands (of Littre) found in males and females?
beneath BM - subepithelial CT
what makes the thin limb of the loop of Henle different form a capillary?
“lollipop with wrapper” - cytoplasm around lumenal surface = not in capillaries
what does the extraglomerular mesangial cell do?
messenger between macula dense/distal tubule and juxtaglomerular cell
sits between macula densa and blood vessel
if you see macula dense, where are you?
vascular pole
where is angiotensinogen produced?
liver
what is the only cell that shows artifical borders between cells?
collecting tubules of Bellini
