Question | Answer |
gametes | = haploid cells produced for sexual reproduction; male= sperm, female= egg |
gonads | = produce gametes; male= testis, female= ovary |
SRY gene | testis determining factor; the indifferent gonad --> becomes testis and secretes TESTOSTERONE and MULLERIAN INHIBITING FACTOR (mullerian duct develops in males, absent in females) |
mullerian inhibiting factor (MIF) | stimulates degeneration of female (Mullerian) ducts --> becomes uterine tube & uterus |
testosterone | stimulates development of male reproductive structures |
homologous structures: genital tubercle | penis or clitoris |
homologous structures: urogenital folds | ventral penis or labia minora |
homologous structures: labioscrotal folds | scrotum or labia majora |
gubernaculum | "pulls" gonads down (from thoracic region to pelvic cavity) --> testes pulled through INGUINAL CANAL: testes extended through SCROTUM; failure= sterility |
puberty | Period of onset of GONADOTROPIN secretion (including FSH and LH) until first menstrual period (females; 12 yrs) or ejaculation of sperm (males; 13 yrs) |
GnRH | from HYPOTHALAMUS; =gonadotropin-releasing hormone, stimulates FSH & LH |
FSH & LH secreted from... | anterior pituitary |
LH stimulates... | LH (in response to GnRH) → stimulates interstitial cells of testes → secrete testosterone |
FSH stimulates... | SUSTENTACULAR CELLS --> secrete androgen-binding protein (ABP) into lumen of seminiferous tubules |
effects of testosterone on body | growth of the sex organs, body growth, dihydrotestosterone (DHT) --> development of the pubic, axillary, and facial hair and apocrine glands, rising rate of sperm production, stimulates BRAIN and awakens the LIBIDO (sex drive) |
FSH & LH negative feedback | TESTOSTERONE (stimulates LH) = inhibits GnRH secretion by hypothalamus & GnRH sensitivity of pituitary; SUSTENTACULAR cells= secrete INHIBIN --> limits FSH production |
spermatogenesis | =process of sperm production: from MEIOSIS to SPERMIOGENESIS, 1st location = yolk sac --> colonize gonads --> spermatogonia |
meiosis | diploid cell 2n (23 PAIRS of chromosomes) --> 4 HAPLOID cells (23 unpaired chromosomes); # chromosome is halved, CROSSING OVER occurs |
test question: spermatogenesis vs. spermiogenesis | spermatogenesis= production of sperm; spermiogenesis= process within spermatogenesis |
formation of 4 spermatids (spermatogenesis process) | spermatogonia (2n diploid)= stem cells -->1 PRIMARY spermatocyte enter meiosis I --> 2 SECONDARY spermatocytes enter meiosis II --> 4 spermatids |
spermiogenesis | = differentiation; spermatid becomes SPERMATOZOON (growth of flagellum, shedding of excess cytoplasm --> MATURE SPERM); occurs in SEMINIFEROUS TUBULES, sandwiched in between SUSTENTACULAR CELLS --> blood-testis barrier |
head of spermatozoon | ACROSOME (lysosome w/ enzymes to penetrate ovum; bursts open to get sperm to egg), NUCLEUS (form male PRONUCLEUS of zygote), BASAL BODY (centriole from which flagellum is formed) |
semen | =sperm-containing fluid = mix of secretions from seminal vesicle, prostate, seminiferous tubules |