embryology Flashcards
Intermediate mesoderm gives rise to
urogenital ridge
urogenital ridge gives rise to …(and then)
nephrogenic ridge –>develos into 3 stes of nephric structure –> a. pronephros b. mesonephros
c. metanephros
sets of nephric structure (and area)
- pronephros (upper - cranial most)
- mesonephroes (middle)
- metanephros (lower - caudal most)
pronephros - time
appears at week 4 and then degenerates
pronephros - function
not functional in humans 5
pronephros develops by
the differentiation of mesoderm within the nephrogenic cord to form pronephric tubules and the pronephric duct
mesonephros develops by
the differentiation of mesoderm within the nephrogenic cord to form mesonephric tubules and the mesonephric duct (Wolffian duct)
mesonephric duct is AKA
Wolffian duct
mesonephros - function
- interim kidney for 1st trimester
2. later contributes to male genital center (mesonephric duct)
mesonephros - regression
most of the mesonephric tubules regress, but the mesonephric duct (Wolffian duct) persists to open into urogenital sinus
Metanephros - time
1st appears in 5th week of gestation –> nephrogenesis continuous through 32-36 weeks of gestation
metanephros is functional in fetus in (time)
week ten
metanephros is consist by
- ureteric bud
2. metanephric parenchyma (metanephric blastema)
metanephros is consist by …. (developed by)
- ureteric bud –> derived from caudal end of mesonephric duct
- metanephric parenchyma (metanephric blastema) –> condensation of mesoderm within nephrogenic cord
metanephros is consist by …. (gives rises generally)
- ureteric bud –> collecting system
2. metanephric parenchyma (metanephric blastema) –> nephron
ureteric bud gives rise to (explain)
collecting system: it penetrates metanephric mesoderm to form the ureter, pelvises, calyces, collecting ducts
metanephric parenchyma (metanephric blastema) gives rise to (explain) (and time
nephron –> interaction with uteric dud induce differentation and formation of glomerulus through to distal convolutd tubule (DCT)
- ureteric bud is fully canalized at (10th week)
ureteric bud is fully canalized at
10th week
aberant interaction between ureteric bud and metanephric mesoderm may rsult in
several congenital malformations of the kidney
renal - DCT?
distal convolutd tubule
most common cause of renal system obstruction (hydronephrosis) in fetus (and why)
Ureteropelvic juction - last to canalize
Kidney embryology - last to canalize
Ureteropelvic junction
Oligohydramnios is a
condition in pregnancy characterized by a deficiency of amniotic fluid
Potter sequence (syndrome) is the
atypical physical appearance of a fetus or neonate due to oligohydramnios experienced in the uterus
Potter sequence (syndrome) - mechanism and manifestations
Oligohydramnios –> compression of developing fetus (by the uterus) –> limb deformites, facial anomalies, pulmonary hypoplasia
Potter sequence (syndrome) - presentation
- limb deformites
- facial anomalies (low set ears, retrognathia, flattened nose)
- pulmonary hypoplasia
Potter sequence (syndrome) - presentation - facial anomalies?
- low set ears
- retrognathia
- flattened nose
Potter sequence (syndrome) - pulmonary hypoplasia - mechanism
compression of chest and LACK of aspiration of amniotic fluid into fetal lung
The fetal urine and lungs
The fetal urine is critical to the proper development of the lungs by aiding in the expansion of the airways - alveoli
Potter sequence (syndrome) - cause of death
pulmonary hypoplasia
causes of Potter sequence (syndrome)
- ARPKD
- obstructive uropathy (posterior urethral valves)
- bilateral renal agenesis
- chronic placental insuficiency
Potter sequence (syndrome) - mnemonic
POTTER Pulmonary hypoplasia Oligohydramnios (trigger) Twisted face Twisted skin Extremitiy defects Renal failure (in utero)
MC congenital renal abnormality
Horseshoe kidney
Horseshoe kidney - defnition
interior poles of both kidneys fuse abnormally
Horseshoe kidney - function?
normally
Horseshoe kidney - location
As they ascend from pelvis during fetal development, horseshoe kidneys get trapped under inferior mesenteric artery and remain low in the abdomen
Horseshoe kidney is associated with
- hydronephrosis (eg. ureteropelvic junction)
- renal stones
- infection
- chromosomal aneuploidy syndromes (Turner syndrome, trisomies 13, 18, 21)
- renal cancer (rarely)
Unilateral renal agenesis - mechanism and defintion
ureteric bud fails to develop and induce differentation of metanephric mesenchyme –> COMPLETE ABSENCE OF KIDNEY AND URETER
Unilateral renal agenesis - definition
complete absence of kidney and ureter
Unilateral renal agenesis - diagnosis
often perinatally via ultrasound
Multicystic dysplstic kidney - mechanism and defintion
Ureteric bud fails to induce differentiation of metanephric mesenchyme –> nonfuctonal kidney consisting of cysts and connective tissue
Multicystic dysplstic kidney - definiton
nonfuctonal kidney consisting of cysts and connective tissue
Multicystic dysplstic kidney - diagnosis
often perinatally via ultrasound
Duplex collecting system - mechanism/defintion
- Bifurcation of ureteric bud before it enters the metanephric blastema creates a Y-shaped bifid ureter.
- Duplex collecting system can alternatively occur through two ureteric buds reaching and interacting with metanephric blastema
Duplex collecting system - is strongly associated with
- vesicoulateral refelx
- ureteral obstruction
- high risk of UTIs
Congenital solitary functional kidney - defintion/mechanism
Condition of being born with only one functional kidney
Congenital solitary functional kidney - clinical presentation
Majority asymptomatic with compensatory hypertrophy of contralateral kidney, but anomalies in contralateral kidney are common –> increased risk of rena failure later in life
which kidney is taken during donor transplantation (and why)
Left kidney is taken during donor transplantation because it has a longer renal vein (implantation advantage)
kdiney - shape
bean shaped organ
Renal blood flow
renal artery –> segmental artery –> interlobar artery –> arcuate artery –> interlobular artery –> afferent arteriole –> glomerulus –> efferent arteriole –> vasa recta/peritubular capillaries –> venous outflow
peritubular capillaries are
tiny blood vessels that travel alongside nephrons allowing reabsorption and secretion between blood and the inner lumen of the nephron
Arcuate arteries of the kidney - location
border of the renal cortex and renal medulla.
glomerulus structure - inner of vessel lumen (to collecting system)
endothelial cells –> basement membrane –> podocytes (visceral layer) –> Bowman space –> Parietal layer of Bowman capsule
glomerulus structure - outer of vessel lumen (away from the collecting system)
- Juxtraglomerular cells (next to afferent arteriole)–> Macula densa –> distal convoluted tubule
- mesangial cells
Components of glomerular filtration barrier (only the components)
- Endothelial cells
- Basement membrane
- Podocytes (visceral layer)
Bowman capsule - layers (and location)
- Podocytes (visceral layer) –> to vessel lumen
2. Parietal layer of Bowman capsule –> away from the vessel lumen
mesangial cells function
- remove trapped residues and aggregated protein from the basement membrane thus (filter free of debris)
- The contractile properties of mesangial cells have been shown to be insignificant in changing the filtration pressure of the glomerulus
ureters: coarse
RETROPERIOTENEAL
the ureters pass UNDER uterine artery (women) or UNDER vas deferens on the way to the urinary bladder at the ureteral orifice
mneomoni: Water (ureters) under the bridge (uterine artery, vas deferens
ureters: coarse –> mneominic: Water under the bridge - water? bridge?
water –> ureters
bridge –> uterine artery, vas deferens
Gyeclogic procedures - uteres course –> clinical significance
Gynecologic procedures (eg. ligation of uterine or ovarian vessels) may damage ureter (ureters pass UNDER uterine artery) –> ureteral obstruction or leak
ureters terminates in the urinary bladder through .. (and area)
postero-lateral angles of the trigone
Trigone of urinary bladder is a
smooth triangular region of the internal urinary bladder formed by the two ureteral orifices and the internal urethral orifice.
Median umbilical ligament - significance
It may be used as a landmark for surgeons who are performing laparoscopy, such as laparoscopic inguinal hernia repair.
Median umbilical ligament is the remnant of the (and location according to bladder)
embryonic urachus
location: superior of the the middle of the bladder
Horseshoe Kidney - chromosomal aneuploidy syndromes
turner, trisomies 13, 18, 21
