session 2 - development of the urinary system Flashcards
what is the blood supply to the left and right kidney
The kidneys are supplied with blood via the renal arteries, which arise directly from the abdominal aorta,
why do we say that three system develop sequentially when talking about the development of the kidney
disappearance of one system marks the onset of development of the next developmental stage
the first to appear is the pronephros in the cervical region
what happens when the pronephros dissapears
the mesonephros is formed
mesonephric tubes develop caudal to the pronephric region
mesonephric tubules plus mesonephric duct = embryonic kidney
does NOT have a water conserving function
what is the pronephros
it is a duct that extends from the cervical region to the cloaca and it drives the development of the next developmental stage
what is the urogenital ridge
it is a region of intermediate mesoderm giving rise to both the embryonic kidney and the gonad
why is the mesonephros important
the mesonephric duct has an important role in the development of the reproductive system in the male
and the mesonephric duct sprouts the uteric bud which induces the development of the definitive kidney
what is the uteric bud
it is undifferentiated intermediate mesoderm, caudal to the mesonephros.
and it induces the development of the true kidney, metanephros
how does the metanephros form
the uteric bud contacts the metanephric blastema (primitive clump of cells)
the bud expands and branches
the collecting system is dervied from the uteric bud
the excretory (nephron) component is derived from intermediate mesoderm under the influence of the the ureteric bud
in what region does the metanehpric kidney first appear
the pelvic region
how does the metanephric kidney move from the pelvis to the abdomen
migration and expansion of the caudal region of the foetus
what is pelvic kidney
Embyrologically, the kidneys develop in the pelvis, and ascend into the abdomen. Occasionally, one of the kidneys can fail to ascend, and remains in the pelvis, at the level of the common iliac artery
what is a horseshoe kidney
A horseshoe kidney (also known as a cake kidney or fused kidney) is where the two developing kidneys fuse into a single horseshoe-shaped structure.
This occurs if the kidneys become too close together during their ascent from the pelvis to the abdomen – they become fused and consequently ‘stuck’ underneath the inferior mesenteric artery.
This type of kidney is still drained by two ureters, and is usually asymptomatic, although it can be prone to obstruction.
what is renal dysgenesis
Renal dysgenesis is used to describe any underdevelopment of the kidneys. There are two main forms:
Renal agenesis – complete failure of one or both kidneys to develop. It is most commonly unilateral.
if unilateral it is compatible with life
Renal hypoplasia – the kidneys develop with a normal architecture, but are of a smaller size.
why might having an additional ureter be problematic
the ureter may not exit via bladder
it could enter the vagina causing incontinence
what does the urorectal septum do
the urogenital sinus is created from hindgut by urorectal septum
the urogenital sinus is continous with the umblicus
it divided the urinary and GI tracts
when the urorectal septum meets the cloacal membrane you get the formation of the perineum
