renal histology & embryology Flashcards
most urinary & reproductive systems are formed from _____ mesoderm
intermediate
3 sections that intermediate mesoderm differentiates into (cranial to caudal)
pronephros
mesonephros
metanephros
fate of pronephros
obliterates early in development
first fate of mesonephros
breaks into segments as pronephros obliterates
what are the segments that mesonephros breaks into called, & what is their function
primordial kidneys
concentrate & excrete liquid waste
waste drainage pathway from segmented mesonephric mesoderm
segmented mesonephros
->
mesonephric duct (aka Wolffian duct)
->
cloaca
fate of metanaphros
definitive kidney
is metanephros segmented?
NO
cloaca gives rise to _____
bladder, urethra, & rectum
mesonephric duct -> becomes _____ -> becomes _____ & grows towards _____
becomes ureteric bud
->
becomes ureter
grows towards metanephros
allantois is a _____ extension of _____
ventral extension
cloaca / UG sinus
nitrogenous waste drainage pathway from UG sinus
UG sinus
->
allantois
->
amniotic fluid
cloaca location & lined by _____
at caudal end of gut tube
lined by endoderm
fate of allantois
becomes urachus in fetus
->
collapses when umbilical cord tied off
->
becomes median umbilical ligament post-natal
clinical condition if urachus doesn’t close
urine leaks from umbilicus (belly button)
the bladder is a dilation of _____
the UG (urogenital) sinus
_____ divides the cloaca into _____ ventrally and _____ dorsally
urorectal septum
UG sinus ventrally
&
anorectal canal dorsally
clinical condition if urorectal septum doesn’t form fully
urorectal / rectovaginal fistula
at day _____, ureteric bud penetrates _____ & begins to _____
day 32
ureteric bud penetrates metanephric blastema
bifurcate (1-3 million times)
_____ forms a cap on each new tip of the ureteric bud
metanephric mesoderm
the “cap” on ureteric bud made of metanephric mesoderm breaks off & becomes _____
renal vesicle
renal vesicle (used to be cap on ureteric bud) then merges w _____
collecting duct (previously ureteric bud)
-so merges back w old bud
4 things renal / nephric vesicle gives rise to
DCT
LoH
PCT
Bowman’s capsule
functional renal corpuscles first arise in metanephros at _____ (age of fetus)
10 weeks
what 2 structures meet at the trigone, & what does this mean for the trigone
ureters & bladder
trigone is mixed
gonad movement during development
gonads are faithful- they drag their vessels & nerves along w them like dog on a leash
(start high, end low)
kidney movement during development
kidneys are promiscuous- swap arteries as they ascend like climbing a ladder
(start low, end high)
the _____ is the functional unit of the kidney
nephron
2 types of nephrons
juxtamedullary nephron
cortical nephron
juxtamedullary nephrons
-location
-glomerulus features
-% of nephrons in the kidney
medulla
glomerulus more internal
large glomeruli
15% of nephrons in kidney
cortical nephrons
-location
-glomerulus features
-% of nephrons in the kidney
cortex
glomerulus more external
small glomeruli
85% of nephrons in kidney
components of the renal corpuscle
= glomerulus + Bowman’s capsule
glomerulus histological composition
capillary bundles lined w endothelium
Bowman’s capsule histological composition
simple squamous epithelium
intraglomerular mesangial cells
-location
-structure
-function
glomerulus
actin & myosin (are contractile)
maintain filtration rates (by making sure capillaries have enough space between them to function)
podocytes
-location
-structure
-function
epithelial cells around capillaries
long foot processes- create filtration slits
filters
3 layers of filtration barrier in glomerulus- & which layer is primary filtration layer
(lumen)
podocytes
basement membrane (basal lamina)
fenestrated endothelial cells
(capillary)
primary filtration layer = basement membrane
juxtaglomerular apparatus = _____ & _____
juxtaglomerular (JG) cells
&
macula densa cells
macula densa cells are sensitive to changes in _____, which is detected by _____;
macula densa cells then signal _____ to _____
sodium (NaCl)
detected by afferent arterioles
signal juxtaglomerular (JG) cells
to increase / decrease renin production
2 cell types in collecting duct
principal cells
intercalated cells
principal cells
-location
-function
collecting duct
water reabsorption & Na+/K+ transport
intercalated cells
-location
-histological feature
-function
CCD, OMCD
darker cytoplasm
acid-base homeostasis
minor calyx is lined w _____, which is helpful for function bc _____
transitional epithelium
good stretch for volume changes
3 tissue layers of bladder, & what is the first layer made of
mucosa (transitional epithelium & lamina propria)
longitudinal smooth muscle
circular smooth muscle
renal blood flow pathway
