Reproduction + Development Flashcards
Why is sexual reproduction an advantage?
Advantageous over asexual reproduction because promotes genetic variety among members of a species
external fertilization
Aquatic animals- external fertilization- gametes meet outside the body; Many gametes are released to ensure perpetuation of the species
internal fertilization
Terrestrial animals- internal fertilization- male delivers sperm directly into the body of a female; Moist tissues inside female provide medium for movement of sperm
Hermaphrodism-
where single individual produces both egg and sperm
Spermatogenesis-
process of forming sperm- occurs in testes; Takes place in seminiferous tubules;
testes
male gonads
seminiferous tubules
hollow tubes within each testis
process of sperm development
Process- spermatogonia primary spermatocytes secondary spermatocytes spermatids mature sperm cells
Sperm cells
Head- contains nucleus with 23 chromosomes, covered by acrosome- contains enzymes which break through the egg
Midpiece- first part of flagellum that contains mitochondria, providing energy for flagella to swim
Tail- remainder of flagellum, arranged in 9+2 array of microtubules
what part of sperm specifically doesn’t enter zygote?
mitochondria of sperm don’t enter zygote
9 + 2
9 couplets surrounding 2 singlets
Sertoli cells-
large cells that surround the seminiferous tubules; prevent sperm from entering bloodstream; Forms compartments that separate sperm cells in different stages of development
Scrotum-
skin covered sac that contains the testes; Maintains temperature slightly below body temp, which is optimal temp for sperm production
(body is 37, scrotum is 35)
What happens after sperm leave seminiferous tubules?
pass into epididymis
What happens after sperm pass into epididymis?
move into vas deferens
vas deferens
sperm duct that extends from the scrotum into the pelvic cavity
What happens after sperm move into vas deferens?
Empties into short ejaculatory duct, then passes through prostate gland, then enters single urethra and leaves the body
Semen-
sperm cells and secretions from glands
Reproductive glands of male
Seminal vesicles, Prostate gland, Bulbourethral glands
prostate gland purpose in reproduction
produces basic fluid that helps neutralize acidic environment of vagina
Bulbourethral glands
paired, located on either side of urethra- releases mucous during sexual arousal, which helps lubricate the penis
Seminal vesicles-
secrete fluid which provides nutrition (fructose) and energy for the sperm
Penis-
erectile organ that delivers sperm into the female reproductive tract; When male is sexually stimulated, blood fills blood vessels in erectile tissue, causing tissue to swell and erection to occur
Testosterone-
male sex hormone; Produced by interstitial cells in the testes; Produces male primary sex characteristics and Stimulate development of secondary sex characteristics at puberty; FSH and LH secreted by pituitary stimulate production of testosterone and spermatogenesis
Insufficient testosterone
sterility
male primary sex characteristics
growth of reproductive organs and spermatogenesis
male secondary sex characteristics
growth of facial and body hair, muscle development, deepening of voice
Oogenesis-
process of ovum formation; takes place on ovaries
ovaries
the female gonads that lie in the pelvic cavity. Each ovary connects to an oviduct-
process of oogenesis
Process- oogonia primary oocytes secondary oocytes ovum
Follicle-
on ovary, primary oocyte and granulosa cells, which form a protective barrier around the oocyte
Follicle cells secrete estrogen as follicle develops