Ch 20 - Reproductive System

Question 1

Sex Determination

Answer 1

Sex is determined by the presence or absence of the Y chromosome. Y = male, Y absent = female

Question 2

Sex Differentiation

Answer 2

Hormonal influence, child rearing, external genitalia presence, internal genitalia

YO: Non viable combination, one X must be present
XO: Turner’s syndrom - characterized by physical deformities including aortic coarctation, webbed skin in neck, shield like chest, sterility and short stature
XXX: “superfemale” associated with mental retardation
XYY: “supermale” associated with mental retardation, heavy facial acne, usually tall stature
XXY: Klinefelter’s syndrom - tall stature, eunuchoid, frequently sterile
Psuedohermaphrodite male: female phenotype, external genitalia look female due to non closure of urogenital slit and cryptorchidism. May have breast development due to adrenal estrogen and may be hyper sexual
Psuedohermaphrodite female: male appearance, may menstruate, may have adrenal genital syndrome

Question 3

Gestation - Male

Answer 3

7-12 week of intrauterine life, Y chomosome codes for testosterone production from testes. Male gonaducts (Wolffian) system is stimulated while Mullerian Inhibiting Hormone is produced from testes to suppress female gonaduct (Mullerian) system. Gonad differentiates into testis with medullary differentiation to make numerous seminiferous tubes while cortex atrophies into tunica albuginea.

Question 4

Gestation - Female

Answer 4

No hormonal actin needed - lack of testosterone influence after the 12th week will favor degeneration of Wolffian system and continued proliferation of Mullerian System. Gonads differentiate into ovaries with cortical differentiation while medulla fills in with stroma (connective tissue)

Question 5

Gonadal Descent

Answer 5

Both gonads descent absolutely and relatively.
Relative descent is due to upper torso growing further than lower torso and absolutely by action of the gubernaculum that connects gonads to the labio-scrotal swelling (guide gonadal descent).

Testes descent to scrotum by way of the inguinal canal while ovaries are hung up on the broad ligament of the uterus and connect ovarian fimbrium of the oviducts.

Question 6

Testes

Answer 6

Seminiferous tubules lined with primordial germ cells that undergo meiosis to produce sperm.
Interstitial cells of Leydig produce testosterone.
Sustentacula (Sertoli) cells nurture spermatids, and produce an