Embryo Flashcards
(45 cards)
what type of mesoderm gives rise to the urinary system and parts of the genital system?
intermediate mesoderm
What gives rise to the nephrogenic cord? what does it give rise to?
- the urogentical ridge (intermediate mesoderm found on either side of the dorsal aorta)
- Pronephros, mesonephros, metanephros
Order of kidney development: urogentical ridge–>
nephrogenic cord–>pronephros–>mesonephros–>metanephros
When does the pronephros develop? when does it degenerate?
- early 4th week (located in cervical region; open into the cloaca)
- day 24-25 (but pronephric ducts persist)
When does the mesonephros develop? what structures does it give rise to? when does it degenerate?
- late 4th week (caudal to pro); functions wk 6-10
- first the mesonephric duct, and then the mesonephric tubules
- Wk 12 (all but the efferent ductiles and sperm passageways)
Where does the mesonephric duct come from?
the leftover pronephros
-functons to drain any formed urine
How are the mesonephric tubules formed?
- interaction of ducts with nephrogenic cord (intermediate mesoderm)
- form renal corpuscles (medial end of the tubules is a cup-shaped glomerular capsule
When does the metanephros from? what two structures are associated?
- week 5 (functional kidney by week 9/10)
2. Uteric bud (outgrowth of mesonephric duct) and metanephric blastema (from nephrogenic cord)
What is the function of the fetal kidney?
to produce amniotic fluid
How is the renal pelvis formed?
the steric bud elongates and penetrates the blastema
How are the ureters formed?
stalk of steric bud becomes them
How are the calices formed?
- 1st generations (4) of tubules enlarge–>major calices
2. 2nd generation (4)–>minor
What involving the uteric bud and the MB is vital to allow proper kidney development?
reciprocal inductions
Five steps of Nephron development
- Arched collecting tubule induces cells of MB to form metanephric vesicles
- These vesicles elongate to form metanephric tubules
- Proximal end will form glomerular capsule and is invalid by glomeruli (blood supply)
- other end of the tubule lengthens and differentiates into the PCT, DCT, and nephron loop
- Each DCT contacts an arched collecting tubule (now connected)
The nephron is derived from? collecting tubule?
- MB
2. U. bud
When do the kidneys reach their adult position in their ascent?
the 9th week (now in contact with suprarenal glands)
What is the cause of unilateral renal agenesis?
U bud doesn’t develop or it degenerates too soon (so no communication with MB)
What does the urorectal septum separate?
bladder (urogentical sinus) and rectum (anorectal canal) parts formed by cloaca
What are the three parts of the urogenital sinus?
- Vesical part (forms most of urinary bladder)
- Pelvic part (forms neck of bladder, prostatic urethra (m), urethra (f))
- Phallic part (spongy urethra (m), lning of vaginal vestibule (f))
When is the mesonephric duct incorporated into the posterior wall of the bladder?
4-6 weeks
What is the trigone?
triangular region of the mesonephric and ureteric ducts blending into posterior bladder
*intermediate mesoderm
The bladder develops mainly from…
the vesical part of the urogenital sinus
How is the urachus formed? what is is called after birth?
- allantois constricts and becomes ligamentous
2. median umbilical ligament
Exstrophy of the bladder is a ___ ____ problem.
body folding (4th week)
- defective closure of ventral abdominal wall
- exposure of mucosa of the posterior wall of bladder
