Test 1 Flashcards
Although the sex is determined genetically at the point of fertilization, the gonads do not acquire male or femal characteristics until the _______ week of development
7th
What is the testis-determining factor?
The key to sexual dimorphism -> Sex Determining Region (SRY) - found on the short arm of the Y chromosome. Without this, female development is established.
Where do mesenchymal or stem cells or primordial germ cells develop?
In the wall of the yolk sac near the allantois
Where do mesenchymal or stem cells or primordial germ cells migrate to?
They migrate along the mesentery of the hindgut until they reach the gonadal ridges and penetrate into the primitive gonad
by the 6th week
What happens before and during the arrival (MIGRATION) of the primordial germ cells?
the overlying epithelium of the genital ridge proliferates and penetrates the underlying mesenchyme forming a number of primitive sex cords - no sex differentiation yet
What are primitive sex cords?
structures that contain hormones and develop from the gonadal ridge. After sexual differentiation -> cell clusters of primitive germ cells then follicular cells around oogonia or testis cords
Both names for male genital ducts
- Mesonephric duct
2. Wolffian duct
Both names for females genital ducts
- Paramesonephric duct
2. Mullerian duct
primordial germ cell migration order
yolk sac -> hind gut -> mesenchyme of the genital ridge -> gonadal ridge -> ovary
In males what does the distal mesonephric duct become?
seminal vesicles, ejaculatory duct, and the vas deferenes
in males what does the proximal portion of the mesonephric duct become
rete testies, efferents, and epididymis - drains the testes
in females what does the cranial end of the paramesonephric duct form?
fallopian tube
in females what does the caudal end of the paramesonephric duct form?
comes into close contact with opposing paramesonephric duct just separated by a septum -> eventually fuses together to form the uterine canal -> uterus, cervix, and vagina
In females the urogenital sinus forms what?
The posterior wall forms the lower 2/3 of the vagina
and the anterior portion forms the urinary bladder and urethra
Contact of the urogenital sinus by the paramesonephric ducts induces the formation of what?
the sinovaginal bulb - a collection of endoderm
What becomes of the sinovaginal bulb?
first -> proliferation forms a solid column of endodermal tissue
second -> the tissue canalizes to form lower 2/3 of vagina
third -> canalization continues forms hymen with central opening
What is DES? why is it used and when?
Diethylstsilbesterol -> “morning after pill” but to save pregnancys - used in the 40s and 50s
Names the male and female homologue of the Gonads
Males - testes
Female - Ovaries
Names the male and female homologue of the Genital tubercle
Male -Penis
Female - Clitoris
Names the male and female homologue of the Urethral Swellings
Male -Scrotum
Female - Labia Majora
Names the male and female homologue of the Urethral Folds
Male -Spongy urethra
Female - Labia Minora
Names the male and female homologue of the Urogenital Sinus
Male - Bladder, Cowpers gland, Urethra, Prostate
Female - Skeens Gland, Lower Vagina, Urethra, Bladder, Bartholins Gland
Names the male and female homologue of the Wolffian Duct
Male -Rete testis, Epididymis, Vas Deferens, Seminal Vesicles
Female - rete ovarii
Names the male and female homologue of the Mullerian Duct
Male -Appendix Testis
Female - Fallopian Tubes, Uterus, Cervix, Upper Vagina
Each breast contains 15-20 __________ separated by adipose tissue
lobes