Embryology of the urinary tract Flashcards
When does the renal system start to develop?
week 5
How many phases are there in renal embryological development?
3
Where does embryo develop from in the embryo?
sacral part of the embryo -> the intermediate mesoderm
Kidneys in adults are placed where
posterior abdominal wall
What are the 3 parts of the mesoderm?
paraxial mesoderm
intermediate medoserm
lateral mesoderm
What is the intermediate mesoderm?
Neck region
What are pronephros?
Lower cervical region of the grwoing embryo -> get segmentation there to form the prnephros
they wont develop completely functional things, they do occurr in the cervical region
What is the mesonephros?
It is the 2nd stage of development
segmentation along the longitudinal duct, it does function for a period unlike pronephros
forms a connection to the vasculature and then binds to the mesonephric duct
What is the importance of having a functional kidney at birth?
urine production is important as it helps in the production of the amniotic fluid
What do mesonephric tubules do?
40 paords produced cranionephrapllythey regress at the end of week 5
20 pairs remain at L1 - L3
differentiate to form the glomerulus and excretory units
function between weeks 6-10
then they regress
When do the mesonephric tubules regress?
Week 10
Do the nesnephric tubule regress completely in men or women?
in women
What happens if th eureteeric bud fails to develop btw the cloaca and the metanephric blastema or is short what happens?
one side - can live with it
both sides - can’tdeal with it
mesonephric duct
forms the collecting tubule
What does the ureteric bud form?
the collecting system: ureteer renal pelvis mahor calyces minor calyces 1-3 million collecting ducts
How does the kidney feel in the embryo?
lobular structure, not smooth
How are multiple collecting ducts, major and minor calyces formed?
the dcts keep growing but at the end forms a aperiod of intususseption. where the multiple major calyces come together and form a big major calyces
similarly again growth and intusussception to forms minor calyces
multiple channels are formed and they cause the formation of millions of collecting ducts
What are the various components of the nephron?
Bowmens capsule
proximal convoluted tubule
ascending and descending loop of Henle
distal convoluted tubule
Formation of the nephron
as a new branch is formed its tip is associated with metanephric tissue caps
helps to feedback to the collecting system (communication system) and its tells collecting tubules to collect fluid and it tells the metanephric tissue to form new nephrons
arrange themselves as a vescile -> an epithelial wall around a hollow spacem it’l l keep growing one towards the vasculature and the other end towards the ureteric bud
the nephron develops as a different structure from the collecting duct and then as it develops the wall btw it and the collecting duct breaks down
How does the kidney reach its adult location?
It moves up during the process of development
ascends from the pelvis to L2 during the wees 6-9
new vessels form as the kidney
What is the arterial supply to the kidney at the beginning and later on?
in the beginning common iliac artery
then as it ascends it gets new branches
Is arterial variation common or rare in the kidney?
It is quite common to find accessory arterial supply
What are a few of the developmental anomalies in the development?
The kidney doesn’t ascend and remains in the pelvic region - pelvic kidney
Horseshoe kidney - ascends anterior to the aorta (fine for a period of time but once the anterior branches of the aorta coome out - it gets trapped under the lowest branch/ IMA, the kidney will be fine but can jave associated problems)
What is the embryological development
endodermal origin
Hindgut endoderm
Urogential sinus divides into what?
bladder- most cranial part
pelvic urethra
expansion of the definitive urogential sinus
Allantois
temporary communication
posterior aspect of the anterior abdominal wall - can find the remnant of the allantois
Incorportation of the mesonephric ducts into the pposterior wall importance
formation of the trigone
is coming from the mesonephric duct, as a result of its different origin it is non-contractile and the musculature is different
Failure of the segregation of the cloaca leads to what?
males in urethra
females along with the development of vagina
leads to the communication btw the systems
