Development of Urinary system

Question 1

describe the formation of the bladder and its origin

what was the allantois and what does it become
and what does this structure become in adult

Answer 1

1. Origin: Urogenital sinus (anterior part of cloaca), posterior: anorectal lumen
2. upper part and the largest part of the urogenital sinus becomes the bladder
3. allantois was the original point of exit of cloaca (faeces and urine) content. Degenerates and is replaced by fibrous tissue = URACHUS
4. urachus is continuous with anterior: umbilicus, posterior: apex of bladder

Adult: umbilicus membrane ligament

Question 2

what are the urachal congenital malformations: 3

Answer 2

1. urachal fistula: urachus remains patent, allowing the content of the bladder to spill via umbilicus
2. urachal cyst: due to the epithelial cells growth, forming cyst: common
3. urachal sinus: partially patent urachus, content of urachus leaks (not urine)

Question 3

which part of the urogenital sinus forms BOTH the male and female urethra

Answer 3

the distal part of the urogenital sinus, continuous with the bladder

Question 4

what is the dual origin of the male urethra

Answer 4

1. prostate urethra and membranous urethra and half of the spongy urethra (penile) = urogenital sinus
2. glans urethra: the ectodermal ingrowth from the tip of glans towards spongy urethra

Question 5

describe the 3 stages of kidney formation and their main points

Answer 5

1. pronephro stage:
   - where there are clusters of cells and prenephro ducts and tubules (tubules empties into duct)
   - at the cervical region
   - degenerates, ducts become the component of next stages
2. mesonephro stage:
   - acts as interim kidneys for 4 weeks, starts forming when the pronephros degenerate
   - elongated organ, caudal to pronephro
   - UPPER THORACIC to UPPER LUMBAR
   - presence of glomeruli, mesonephro duct and tubules
   - presence of nephrogenic cord (its a tissue surrounding the tubules)
3. metanephro stage: forms when the mesonephro degenerates
   - becomes the permanent kidneys, 2 sources
   - the distal mesonephric duct: becomes the URETERIC BUD
   - the nephrogenic cord: metanephric blastema

Question 6

what does the ureteric bud and metanephric blastema become

Answer 6

ureteric bud: the collecting portion: papilla, major and minor calyx, renal pelvis

metanephric blastema: convoluted tubules, bowmans capsule, collecting duct etc

Question 7

describe the ascend and rotation process of the kidney and kidney hilum

Answer 7

1. kidney hilum: ventral facing, rotates 90 degrees
2. ascend = ‘apparent’
   - is a pelvic organ, suppled by the middle sacral arteries
   - LUMBOSACRAL region grow, and URETER grow
   - now: upper lumbar arteries supply

these are all transitional arteries, eventually = renal artery

• right lobe of liver prevents the right kidney from ascending to the left kidney’s height