embryogenesis 9 Flashcards
what are the three stages (types) of kidneys present in development
Pronephros – vestigial/non-functional
Mesonephros – may function transiently in embryonic life
Metanephros – definitive kidney. Fish and amphibians there is no metanephros
what does the intermediate mesoderm give rise to?
kidneys and gonads (genital ridge)
describe the location, development and final form of the pronephros
Located around each of the somatic cord (nephrotomes)
From the intermediate mesoderm to the pronephric tubules, these then form the pronephric duct, which joins the coelomic cavity
Forms internal glomeruli/tubules of primitive kidney
describe the location, development and final form of the mesonephros
Lateral to urinary ridge the pronephric duct induces mesonephric tissue to form tubules and renal corpuscles
Develops at the end of the somite stage, the intermediate mesoderm in the thorao-lumbar region forms a column of tissue called the urogenital ridge. the structres can be seen as they pull away from the genital ridge.
Later forms medial genital ridge and lateral genital ridge
Development of mesonephric system causes what to atrophy
pronephric tubules and cranial portion of pronephric duct
describe the location and development of the mesonephros
Ureteric bud extends cranially towards blastema and is surrounded by metanephric tissue
Dilated end forms pelvis and collecting ducts of definitive kidney
Collecting duct formation induces tissues to form metanephric tubules
From ureteric bud and metanephric blastema at caudal end of nephric ridge about sacral region
what genes control the development of the kidneys
Pax2 and Pax8 genes
the nephric ducts grow by another method other than cell recruitment, how?
intrinsic duct growth
descrube the development of the nephric duct
Duct initially solid and requires the presence of neighbouring epidermis to form a tube.
If tip of duct destroyed further growth inhibited
Bud induces tubule formation
what is the diffrence between primary and secondary sex determination
primary - Development of the ovaries or testes (internal)
secondary - Development of the external genitalia
what is the precurser to both of the gonads
bipotential gonad. (Intermediate mesoderm adjacent to mesonephric ridge, the most ventral aspect is the genital ridge (epithelial layer))
what is the sexual indiffrent stage?
deviation of the bipotential gonad has not occurred. it still has both the Mullerian (paramesonephric duct) and Wolffian (mesonephric duct) ducts present
in the male, describe the deveopment of the paramesonephric and mesonephric duct
The mesonephric ducts persits and the paramesonephric ducts degenerate
in the female, describe the deveopment of the paramesonephric and mesonephric duct
The mesonephric duct degenerates and the paramesonephric ducts persist
what are the three common types of failure in the primary/ secondary sex determination
Pseudohermaphrodism
Female Pseudohermaphrodism
Male Pseudohermaphrodism
what is Pseudohermaphrodism
Single set of gonads, the secondary sex characteristic differ from the primary
what is the sex chromones role in development
The XY changes either supresses or inhibts the expression of genes.
list some important genes to sex development
SF1
WT1
LHX9
DAX1
WNT4
SRY
SOX9
SF1
Shh
what effect does SF1 have
regulates the mullerian duct derivatives
what effect does SOX 9 have
gene regulates the mullerian duct derivatives
what effect does Shh have
Shh controls prostate formation
somatic cells become what
sertoli cells
what do sertoli cells devlop into
Sertoli cells amalgamate and extend to form the testis cords, invading and taking over the structure of the mesonephric kidney. (this can be seen in the connective tissue around the seminiferous tubules in a specific pattern)
