Urinary System II Flashcards
How does metenephros position change during differentiaion?
Changes from pelvic to the lumbar region
With respect to the degenerating mesonephros, where is the definitive kidney located?
The definitive kidney occupies the position dorsal to the degenerating mesonephros
Explain the migration of the right kidney in domestic animals
With the exception of pigs, the right kidney in domestic animals migrate more cranially than the left kidney
-Left is last and lagging
With development of nephron and collecting duct system how is the kidney organized?
Into outer cortical and inner medullary regions
Parts of the cortex
Renal Corpuscles
Proximal and distal convuluted tubules
Parts of medulla
Loops of Henle
Collecting Ducts
What leads to the term Medullary Pyramid?
Conical arrangement of loops of Henle and collecting ducts
What is the base of the pyramid covered by?
The base of the pyramid is covered by the cortex of the kidney
What is a renal Lobe?
A medullary pyramid with cortical covering
Explain the topography of the pyramid
Base of the pyramid is covered by the cortex of the kidney and the apex as a papilla projecting into the pelvis of the kidney
What are the variations of kidney anatomy between species a result of?
Differences in the branching of the ureteric bud and arrangement of nephrons associated with these branches
In early embryo, caudal end of hindgut terminates in an endodermally lined chamber known as?
The cloaca
What closes the cloaca?
Cloacal membrane
What type of tissue is found between the hindgut and base of the allantois, and what is it called?
Mesodermal tissue called the urorectal septum is found between the hindgut and base of the allantois
What occurs as development continues?
As development continues, the septum grows towards cloacal membrane dividing cloaca into rectum and urogenital sinus
Once partitioned, what is the cloacal membrane now split into?
Anal and urogenital membranes
What does the bladder develop from and what does this follow?
Bladder develops from pelvic region fo urogenital sinus (following cloacal partitioning)
What does the more caudal part of the urogenital sinus develop into?
Urethra
What is the urogential sinus continuous with?
The allantois
What is different about the bladder from the rest of the urinary system?
Bladder is endodermally derived, the rest of the urinary system is derived from the intermediate mesoderm
Explain the incorporation of the terminal parts of the mesonephric and ureteric ducts into the bladder
As bladder grows it incorporate the terminal parts of the mesonephric and ureteric ducts
Each duct system though develops own separate opening into developing bladder
Mesonephric ducts are initially anterior to the ureteric buds
Positions gradually shift so ureteric buds finally open into bladder laterally and anterior to the mesonephric ducts
A triangular area in the dorsal wall of the bladder called the trigone marks the region of the mesonephric duct and ureteric bud incorporation
What is renal agenesis?
Complete absence of one (unilateral) or both (bilateral) kidneys.
What can renal agenesis be associated with?
Absence of ureter
What is the most commone congenial kidney condition in pigs?
Unilateral renal agenesis
What is renal agenesis a result of?
THe failure of the development of one or both ureteric buds - so there is no induction of the metanephric mass to form renal tubules
What is renal hypoplasia?
Substantially small kidneys due to immature glomeruli and tubules. Unilateral and bilateral forms
What is the most common renal anomaly in many breeds of dogs?
Renal hypoplasia
How do you treat renal hypoplasia?
Managing associated chronic renal failure
What are the two migration defects of kidney?
Most common form leaves a kidney in pelvic cavity
Another form is crossed ectopia which is one kidney and its associated ureter on the same side as the other kidney
What is horseshoe kidney?
Kidneys become fused at inferior poles. Origin is uncertain.
What are polycystic kidney?
Multiple cysts form in the kidney - organs are enlarged
What are polycystic kidneys a result of?
Failure of developing nephrons to connect with their collecting ducts
What do cysts in polysyctic kidneys arise from?
Accumulation of urine within the nephrons that are isolated from collecting ducts
What is an ectopic ureter a result of?
Improper development of the metanephric duct systems
What is a patent urachus?
Improper closing of canal which feeds through the umbilicus in fetus, improper closing causes for leakage of urine from naval
What are urachal remnants?
Congenital anomaly resulting from imcomplet urachal closure.
