Lecture 25 3/19/24 Flashcards
What is the gonadal ridge?
undifferentiated primitive gonad during early embryonic development
What are the paramesonephric ducts?
part of a primitive kidney system during embryonic development
What is the yolk sac?
evolutionary remnant in mammals that still has functions in early embryonic development
What is the allantois?
part of the placenta involved in the formation of the umbilical cord and the exchange of nutrients/gas/metabolites
What are the characteristics of the primordial germ cells?
-migrate from the yolk sac to the gonadal ridge
-populate sex cords/cortical region of embryonic gonads
-become sperm or oocytes
What is the pronephros?
nonfunctional remnant of primitive kidney
What are the characteristics of the mesonephros?
-bilateral pair of intermediate kidneys
-replace the pronephros
-produce urine
-drained by the mesonephric ducts
What are the characteristics of the metanephros?
-final renal form
-develop functional nephrons
-functional form of kidney in the adult
What is the sexually indifferent stage?
when both the mesonephric and paramesonephric ducts are present, but the embryo is still undifferentiated in terms of sex
What is a true hermaphrodite?
individual with ovotestes or one ovary and one testis
What is a pseudohermaphrodite?
individual in which the gonads are consistent with the chromosomal sex, but the external genitalia is the opposite
Which substance controls the pathway towards being male or female?
testis determining factor/sex-determining region in the Y chromosome
How does testis determining factor (TDF) lead to a male individual?
-induces testicular development and differentiation of Sertoli cells
-Sertoli cells produce AMH (anti-Mullerian hormone)
-AMH induces Leydig cell differentiation and paramesonephric duct degeneration
-Leydig cells produce testosterone and DHT, leading to male duct system development
How does a lack of TDF lead to a female individual?
-absence of TDF allows gonads to develop into ovaries
-paramesonephric ducts give rise to female repro. tract
Which ducts are utilized in the male vs female?
male: mesonephric
female: paramesonephric
Which follicles form the cortex of the ovary?
primordial follicles