Urinary Embryology Flashcards
Hiow many kidney systems develop originally in embryology?
3 sequentially
Disappearance of one system marks the onset of development of the next stage
First appears in the cervical region - pronephros
What are the 3 developmental systems of the kidney?
Pronephros
Mesonephros
Metanephros
What is a nephrotome?
Section of mesoderm giving rise to the pronephros and eventually the rest of the kidneys
Why is the pronephros important?
Never functions in humans but has a duct - pronephric duct extends from the cervical region to the cloaca and drives the development of the next developmental stage
What is the urogential ridgef?
Region of intermediate mesoderm giving rise to both embryonic kidney and the gonad
Where do the mesonephric tubules form?
Caudal to the pronephric region
What constitutes the embryonic kidney?
Mesonephric tubules and the mesonephric duct
What is the importance of the mesonephros?
Duct sprouts the ureteric bud which induces development of the definitive kidney which has an important role in the development of the reproductive system in the male
What is the metanephric blastema?
Gives rise to the true kidney from the ureteric bud
How does teh ureteric bud change during development of the kidney?
Contacts metanephric blastema
Bud expands and branches
forms calices
What forms the collecting system of the kidney?
Ureteric bud
What developmental structure forms the excretory component of the kidney?
Intermediate mesoderm under the influence of the ureteric bud
Describe the “ascent” of the kidney.
Metanephric kidney first appears in the pelvic region
Undergoes an apparent caudal to cranial shift, crossing the arterial fork formed by vessels returning blood from the fetus to the placenta
What happens if the ureteric bud fails to interact with intermediate mesoderm?
Renal agenisis - can survive if only one side
What is wilm’s tumour?
Paediatric tumour of the kidney
What are ectopic ureters?
ureter openings in the wrong place eg. vagina.
Symptoms - incontinence
How do duplication defects of the kidney come about?
Splitting of the ureteric bud - partial or complete. Symptomatic consequence is ectopic ureteral opening causing incontinence
What does multicystic kidney disease cause?
Atresia of ureter
What is the cloaca?
The end of the gastrointestinal, urinary and reproductive tracts.
What is the urogenital sinus created from?
Hindgut by urorectal septum. continuous with umbilicus
Describe the urogenital sinus.
3 parts -
Largest - future bladder
Pelvic and phallic - parts of future urethra
What doe shte female urethra form from?
Urogenital sinus
What does the male urethra form from?
Pelvic part of urogenital sinus forms the pre-prostatic, prostatic and membranous parts nad the phallic part forms the spongy length of the urethra
How is the different male/female external genitalia formed?
In the male, the genital tubercle elongates and genital folds fuse to form the spongy urethra
No fusion occurs inthe female and the urethra opens into the vestibule
What is hypospadias?
Defect in fusion of urethral folds
Urethra opens onto the ventral surface rather than at the end of the glans
