Embryology Flashcards
What are the 3 kidney systems in order of appearance and what are they derived from
Pronephros
Mesonephros
Metanephros
Derived form intermediate mesoderm
Where does the pronephros develop
Cranial region
Where does the pronephric duct extend from and to
From pronephros to cloaca
What makes up the embryonic kidney
Mesonephric tubules
Mesonephric duct
Where do the mesonephric tubules develop
Caudal to pronephric region
What is the urogenital ridge
Region of intermediate mesoderm that gives rise to the embryonic kidney and the gonad
What does the mesonephric duct do
Sprouts the Ureteric bud which interacts with intermediate mesoderm to induce development of the true kidney
Role in development of male reproductive system (regresses in females)
Where does the metanephric blastema develop
Caudal region
How does the Ureteric bud interact with the metanephric blastema
Comes into contact, expands and branches forming the calyces and renal pelvis
What are the collecting and excretory components of the nephron derived from
Collecting - Ureteric bud
Excretory - intermediate mesoderm under influence of the Ureteric bud
Describe apparent kidney ascent
First appear in pelvic region but undergoes caudal to cranial shift (elongation of trunk)
Crosses arterial fork formed by vessels returning to placenta
New renal vessels sprout from aorta, each more caudal, which then regress
What is renal agenesis
Failure of kidneys to develop
Ureteric bud doesn’t interact with intermediate mesoderm
What is pelvic kidney
Failure of kidney ascent
Describe duplication defects
Splitting of Ureteric bud
Leads to accessory ureter which may have an ectopic opening therefore there will be urinary incontinence
Examples of cystic diseases
Multicystic - ureter atresia
Polycystic - autosomal recessive disease
What is wilm’s tumour
Nephroblastoma
Describe horseshoe kidney formation
The 2 developing kidneys become too close on their ascent and their lower poles fuse during lateral rotation
The fused kidney gets caught on the IMA so it remains at the pelvic brim
Parts of the urogenital sinus
Bladder
Pelvic
Phallic
Describe development of the urogenital sinus that is common in both sexes
Mesonephric ducts contact urogenital sinus
Ureteric bud sprouts from mesonephric ducts
Smooth muscle appears and urogenital sinus expands
Describe development of the urogenital sinus that is specific to males
Ureteric buds and mesonephric ducts make separate opening in the urogenital sinus
Mesonephric ducts develop into vas deferens
Prostate and prostatic urethra form
Describe development of the urogenital sinus that is specific to females
Mesonephric ducts regress entirely
Ureteric bud make an opening on the urogenital sinus
Which parts of the urogenital sinus forms the urethra
Pelvic - female urethra
- Pre prostatic, prostatic and membranous part of male urethra
Phallic - spongy part of male urethra
3 parts of the external genitalia
Tubercle
Swelling
Folds
Development of the male external genitalia
Tubercle elongates and folds fuse to form the spongy urethra
Development of the female external genitalia
No fusion of folds
Urethra opens into vestibule
What is exstrophy of the bladder
Bladder opens into abdominal wall
Describe hypospadias
Defect in fusion of male genital folds which leads to the urethra opening onto the ventral surface of the penis
Describe cloacal partitioning
Urorectal septum from hindgut separates the cloaca into the urogenital septum anteriorly and the anorectal canal posteriorly
What connects the urogenital sinus to the umbilicus
Allantois first, then urachus
Adult derivative of urachus
Median umbilical ligament
