Development Of Urogenital And Genital Flashcards
Describe the formation of the urogenital system.
Starts with the intermediate mesoderm which becomes nephrogenic ridges which will give rise to the component of kidney which filters blood.
There is a wave of differentiation and then degeneration cranially to caudally starting with the one day pronephros.
The mesonephros tubule is useful in the embryo in filtering blood (from the GLOMERULUS) and producing urine, the urine enters the mesonephric duct.
The ducts will carry the urine to the cloaca (which has a two layered membrane (endoderm and ectoderm) which will degenerate and then open to the outside world)
The allantois is a duct which exits the cloaca and into the umbilical cord and runs with the vitelline duct coming from the midgut.
The division of the cloaca is a ridge of mesoderm which goes down and fuses with the inferior cloacal membrane and becomes the perineal body. This division creates the UROGENITAL SINUS (bladder) connected to the mesonephric duct and ANORECTAL CANAL which is just an opening of the hindgut now.
Describe amniotic fluid abnormalities
Oligohydramnios - abnormally reduced volume of amniotic fluid
-do to inability to produce urine or obstruction of urinary tract
- results in Potter’s syndrome
- hypoplastic lunes
- underdeveloped limbs
- flattened face
Polyhydramnios - abnormally increased volume of amniotic fluid
- interference of swallowing and absorption of fluid
- results FROM esophageal or duodenum obstruction and loss of swallowing reflex
Describe the development of the adult kidney.
The ureteric bud grows from the MESONEPHRIC duct to the metanephric blastema which becomes the NEPHRON of the kidney (filter).
Reciprocal induction - nephron formed from the metanephric blastema induces ureteric bud to branch into the CALYCES and subsequently the COLLECTING TUBULES which are responsible for conduction (movement of fluid)
The RENAL PELVIS is between the calyces and the ureter
After the kidneys form they “ascend and rotate”
During this ascension new blood supplies are formed and lost, this may result in accessory renal arteries attached to the inferior portion of the kidney.
If you have a horseshoe kidney, your ascent will be caught in the inferior mesenteric artery.
What occurs with the mesonephric duct in males vs females in development.
Describe the paramesonephric ducts
Males: the mesonephric duct becomes the ductus deferens (vas deferens - transport sperm from epididymis to ejaculatory ducts)
-paramesonephric ducts are lost
Females: mesonephric duct is lost
-the paramesonephric ducts are invaginates of the coelom and are therefore continuous with the peritoneal cavity and will later become known as the uterine tube.
-the right and left paramesonephric ducts will fuse to become the uterus and makes contact with the urogenital sinus. When it does it forms the sinus tubercle which will then hollow out and form the vagina.
Describe the internal male reproductive system in ducts and shit
What does the mesonephric tubules become?
So you got the kidney (metanephric blastema) with the ureter.
The mesonephros and the mesonephric duct are no longer useful when the adult kidney has formed.
In females it all degenerates.
IN males the mesonephric duct becomes the ductus deferens (carries sperm), seminal vesicle and ejaculatory duct
The urogenital sinus gives rise to the bladder, prostate and urethra.
There is an evagination of the urogenital sinus where the really short ejaculatory duct meets the urethra. This is the prostate - makes semen
-endoderm in origin while the ducts are mesoderm in origin
Coming off of the ductus deferens is the seminal vesicle
They both converge at the ejaculatory duct which attaches to the urethra.
Mesonephric tubules become efferent ductless which supply the testes
Describe the female reproductive system and its origins.
Mesonephric tubules and duct is not used, vestiges
Paramesonephric duct - uterine tubes, uterus and upper 1/3 of vagina
Urogenital sinus - bladder, urethra, lower 2/3 of vagina
*for some goddamn reason, as we know the urogenital sinus is above the paramesonephric duct so lower vagina refers to the upper portion
Describe the external structures of female and male genitalia and their origins.
Both start off with:
- Genetic tubercle
- Urethral folds, the opening of the urogenital sinus
- The labioscrotal fold (cloaca)
Male: the genetic tubercle becomes the head of the penis
- the urethral folds fuse and becomes the ventral penis
- labioscrotal folds become the scrotum
Females: genetic tubercle becomes the clitoris
- the urethral folds do not fuse and becomes the labia minora
- the labioscrotal folds do not fuse either and are the labia Majora
What is hypospadia?
There is a defect in the fusion of the ventral penis from the urethral folds.
This leads to the opening not at tip of the penis but rather wider and more ventral. You are infertile because your semen can’t go deep into the vagina.
Describe where stones are likely to form in the renal system?
what would be an indication of renal stone?
Renal stone: At the renal-uretero junction
If it is small enough to pass into the ureter, its the ureteral stone.
Two likely regions for ureteral stone is the bifurcation of the common iliac into external and internal.
The third and most common location of the ureteral stone is at the uterovesicle junction (entrance into the bladder)
Look for hydronephrosis, there would be an enlargement of the kidney.
Describe the blood supply to the kidneys
Renal artery enters the hilium > it divides into segmental arteries > it divides into interlobar arteries > which each divide twice to become arcuate arteries to supply one half of two different renal pyramids> interlobular arteries go into the medulla of the kidney off of the arcuate arteries.
Each of these are end arteries.
Describe the process of emptying the bladder? There are 3 muscular components.
Detrusor muscle surrounds the bladder and continues along the urethra (preprostatic in males).
Detrusor muscle is parasympathetic.
(pelvic splanchnics)
Internal sphincter is sympathetic lumbar splanchnics (inferior mesenteric plexus)
External sphincter is somatic (pudendal nerve)
When the detrusor muscle contracts, the vesicoureteral junction will also be closed so there is no reflux up the ureter.
What does “loin to groin” pain mean?
The upper ureter is innervated by Lesser splanchnics and least splanchnics (T10-T12) and the 1st Lumbar splanchnic (L1)
Lower ureter is innervated by the lumbar splanchnics, pelvic splanchnics, and sacral splanchics.
As a stone passes down the ureter it will present with loin to groin pain.
