Chpt 4: Embryonic Development of Reproductive Structures Flashcards
coordinated series of events involving the merging of several types oftissue that will ultimately form complete reproductive glands and organs
embryogenesis
embryonic germ layer that differentiates into the digestive system, lungs, and endocrine system
endoderm
embryonic germ layer that differentiates into muscle, skeleton, cardiovascular, and reproductive system
mesoderm
embryonic germ layer that differentiates into nervous system (hypothalamus, both pituitary lobes), skin (including mammary glands), and hair
ectoderm
gives rise to embryo and germ layers that will develop into various specialized organs
inner cell mass (ICM)
origin of the anterior lobe of pituitary from tissue in the roof of the embryo’s mouth, gives rise to a diverticulum fromthe roof of the mouth and grows dorsally
stomodial ectoderm
diverticulum formed from the stomodeal ectoderm from roof of the mouth, grows dorsally, differentiates to form the adenohypophysis (anterior lobe)
Rathke’s pouch/pocket
diverticulum developed from floor of brain and grows ventrally toward Rathke’s pouch, differentiates to form neurohypophysis (posterior lobe_
infundibulum
contains axons and nerve terminals of neurons whose cell bodies are located in the hypothalamus
posterior (neurohypophysis) lobe
cranial bone that begins to form around both lobes as development of pituitary nears completion
sphenoid bone
protective cavity formed by sphenoid bone surrounding pituitary lobes
sella turcica
nerves cause a direct and rapid release of axytocin that causes milk ejection
posterior lobe
consists of specialized glandular epithelial cells that secrete glycoprotein hormones like FSH and LH that are not secreted by nerve cells
anterior lobe
cells that originate from the base of the hind gut
primordial (primitive) germ cells
means capable of differentiating alongtwodevelopmental pathways, the gonad of the new embryo is like this
bipotential
location of the biopotential gonad, located on inner surface of the dorsal body wall,will eventually form the gonads, forms medial to embryonic kidneys
genital/gonadal ridge
compact strands of tissued caused by the arrival of primitive germ cells in the genital ridge, and the subsequent stimulation of local CT to proliferate, cause the genital ridges to enlarge and push toward the developing kidneys (mesonephros)
primitive sex cords
first distinct renal system, nonfunctional remnant of a primitive form of kidney found in lower animals
pronephros (pronephric kidney)
replaces pronephros early in embryogenesis, functional, bilateral pair of intermediate kidneys, forms urine that is drined by bilateral pair of ducts (mesonephric/ Wolffian ducts)
mesonephros (mesonephric kidney)
drains urine formed by mesonephros, extend caudally and empty into urogenital sinus
mesonephric ducts
final renal form, begins to appear near the firs10-15% of gestation, fully functional by 30-35%, develops functional nephrons, serves as functional form of kidney in adult mammals
metanephros (metanephric kidney)
new pair of ducts beside the mesonephric ducts, begins to develop at same time as mesonephros is developing, form on either side of mesonephric duct
paramesonephric/Mullerian ducts
process regulated by a singl substance directed by gene on Y chromosome (SRY)
Sexual Differeniation
XY chromosomes -> SRYprotein -> testes develop -> sertoli cells secrete anti-Mullerian hormone (AMH) and dihydrotestosterone ->(desert hedgehog (DHH) gene caused differentiation of fetal Leydig cells -> Testosterone -> development of male duct system AND AMH and testosterone degenerate paramesonephric duct -> dihydrotestosterone -> development of penis, scrotum, and accessory sex glands)
Formation of Male Reproductive System
