Urinary Session 2- Development Of Urinary Tract & Histology Flashcards
What is the location of the kidneys?
Retroperitoneal each side of the vertebral column between T12 & L3
Where does the kidney’s blood supply come from?
Direct branch of the abdominal aorta
What are the 3 layers of the trilaminar embryo? (Sem 1)
Endoderm
Mesoderm
Ectoderm
What are the areas within the mesoderm after organisation?
Paraxial mesoderm Intermediate mesoderm Somatic mesoderm Splanchnic mesoderm Intraembryonic coelom
After gastrulation, what are the areas where mesoderm does not separate ectoderm and endoderm?
Buccopharyngeal membrane
Cloacal membrane
Which are of mesoderm does the kidney develop from?
Intermediate mesoderm
Name the areas of the urinary system in the order they develop
Pronephros
Mesonephros
Metanephros
What does a nephrotome consist of?
Glomerulus
Bowmans capsule
Proximal and distal convoluted tubule
Collecting duct
What is the function of the pronephros?
Never functions in humans BUT pronephric duct extends from cervical region to cloaca and drives development of next developmental stage
What is the urogenital ridge?
Region of intermediate mesoderm giving rise to the embryonic kidney and the gonad
What structures form the embryonic kidney?
Mesonephric tubules and mesonephric duct
Where do mesonephric tubules develop?
Caudal to the pronephric region
What is the function of the mesonephric duct?
Sprouts the ureteric bud which induces development of definitive kidney
Important role in development of the reproductive system in the male
What is the function of the ureteric bud?
Induces development of definitive kidney within intermediate mesoderm of the caudal region of the embryo
Collecting system is derived from ureteric bud itself
Excretory component is derived from intermediate mesoderm under influence of ureteric bud
How does the ureteric bud form the definitive kidney?
Ureteric bud contacts metanephric blastema
Bud expands and branches forming renal pelvis, major calyx and minor calyx
Describe what occurs during the ascent of the kidney
Metanephric kidney first appears in pelvic region
Undergoes caudal to cranial shift, crossing arterial fork formed by vessels returning blood from foetus to placenta
As kidneys ascend, new blood vessels form and old ones regress
What can occur when kidney formation goes wrong?
Ureteric bud fails to interact with intermediate mesoderm- renal agenesis Migration goes awry Wilm's tumour Duplication defects Ectopic ureter Cystic disease
How do duplication defects occur?
Splitting of ureteric bud- can be partial or incomplete
Symptomatic consequence is ectopic urethral opening
What are the 3 types of cystic kidney disease and their characteristics?
Multicystic kidney disease- atresia of ureter
Polycystic kidney disease- recessive, presents early, poor prognosis
What is the cloaca?
The structure where the GI, urinary and reproductive tracts end
What is the urogenital sinus?
Created from hindgut by urogenital septum to separate anus and urogenital system
Continuous with umbilicus
What are the 3 parts of the urogenital sinus and what will they become?
Largest part = future bladder
Pelvic and phallic parts = parts of future urethra
How is the prostate and prostatic urethra formed in males?
Mesonephric ducts reach urogenital sinus
Ureteric bud sprouts from mesonephric ducts
Smooth musculature begins to appear, UGS begins to expand
Ureteric buds and mesonephric ducts make independant openings in UGS
How does the development of the urinary system differ in females?
As UGS begins to expand, MD begin to regress
MD regress completely- ureteric bud opens into UGS
