Anatomy Lecture 31_Urinary System Development Flashcards
What embryologic tissue gives rise to the UG system?
intermediate mesoderm)
During development, what are the three kidney systems that develop?
- Pronephroi
- Mesonephroi
- Metanephroi
When does the Pronephroi develop and disappear?
It develops at the beginning of week 4 and is gone by the end of week for. There is no portion of it that is present in the adult.
When does the mesonephroi develop and what is its fate?
It begins functioning around week 4 and stops around week 10. It’s ducts (mesonephric ducts) form the trigone of the bladder in adults and contributes to portions of the male genital system
When does the matanephroi develop and what two structures give rise to it
The metanephroi is the actual kidney. It begins developing week 5 and is functional by week 10. It develops from the Ureteric bud which gives rise to the collecting system, and the Metanephrogenic blastema which gives rise to the excretory units (nephrons)
Describe the Position of the Kidney during development. How does the effect arterial blood supply? What is the clinical significance?
The kidney starts developing in the pelvis and then ascend into the abdomen (the opposit of the gonad). As this happens, new arteries will grow off the aorta to supply blood while old arteries will disappear. This can lead to many variations in arterial blood supply (and venous return). Occationally a persistant artery can impinge on the ureter and the variations are clinically significant in during surgery and trauma (because things that should not be there can bleed. This can also cause a pelvic kidney (does not ascend) or a horseshoe kidney (caudal poles fuse and it gets stuck at the IMA)
What is Renal Agenesis
It is the failure of a ureteric bud to form which in turn prevents the formation of a kidney. If this only occures on one side, renal agenesis will be asymptomatic, if it occures on both sides, the condition will be fatal
Describe Polycystic Kidney Diseases
It can be either autosomal recessive or autosomal dominant. It leads to cyst formation on the kidey which reduces functionality, leads to hypertrophy, and eventual kidney failure.
What does the 1 st part (Vesical part) of the urogenital sinus form?
It forms the bladder (except for the trigone)
What does the allantois become?
It becomes the urachus, a thick fibrous cord that connects the apex of the bladder to umbilicus
What does the 2nd Part (Pelvic part) of the urogenital sinus form?
- In males, gives rise to prostatic and membranous urethra (Epithelium of prostatic urethra will form the prostate gland)
- In females, gives rise to entire urethra (Cranial part gives rise to urethral and paraurethral glands)
What does the 3rd Part (Phallic part) of the urogenital sinus give rise to?
- Grows toward genital tubercle (primordium of the penis or clitoris)
- In males, it gives rise to spongy urethra
- In females, it gives rise to vestibule of the vagina
What is an Ectopic Ureter
It is when there are two ureters and one of them does not enter the bladder but instead joins to a different structure
What is a Urachal fistula
- Allantois persists
* Urine to drains from umbilicus
What is a Urachal cyst
- Local area of allantois persists
- Epithelium lining cyst produces secretions that gradually fill cyst that is fixed in location
- May become tender and cause pain
