Females have ovaries in which eggs form. The eggs travel through an oviduct
into a uterus or uteri. Oviparous females then lay eggs, while viviparous
females bear their young alive. Sperm are produced in the testes of males
and travel through the vas deferens.
- Asexual reproduction: reproduction
without genetic recombination.
- Sexual reproduction: reproduction including genetic recombination.
- Gonochorism: male and female sex organs located in separate organisms.
- Hermaphroditism: both male and female sex organs in the same individual.
- Oviparous: egg-laying. Eggs usually fertilized externally,
but birds and reptiles have internal fertilization requiring copulatory organs.
- Viviparous: giving birth to live young; fertilization always internal.
- Plant reproduction: see review topics 73 and 79.
- FEMALE REPRODUCTIVE ORGANS IN VERTEBRATES:
- Ovaries: female gonads; produce eggs (ova); also estrogen.
- Oviducts (Fallopian tubes): carry eggs from ovaries to uteri.
In birds, a shell gland surrounds egg with protective coatings.
- Uterus: womb where embryo grows. Made of 3 layers:
- Epimetrium: thin connective tissue capsule
- Myometrium: thick, muscular layer
- Endometrium: sensitive, mucus-coated inner layer with
periodic (monthly) fluctuations in thickness (ending in menstruation)
under hormonal control
- Shape of uterus varies:
- duplex: two separate, paired uteri (as in nonmammalian vertebrates)
- bipartite: two separate uteri emptying into a common cervix,
as in many hoofed mammals
- bicornuate: Y-shaped, with two long horns and a common
body and cervix, as in most carnivores
- simplex: a single body and neck-like cervix, as in primates
- Vagina: tubular sheath whose walls secrete a lubricating mucus
- External genitalia in mammals:
- Labia majora: outer folds, dry on outside
- Labia minora: correspond to shaft of male penis; sensitive
inner folds containing erectile tissue (corpora cavernosa)
- Clitoris: corresponds to tip of penis; sensitive erectile
body located where labia minora come together; contains erectile
tussue (corpus spongiosum)
- Hymen: delicate membrane guarding entrance to vagina
- Bartholin's glands: just outside vaginal entrance; secrete
a lubricant that sometimes contains a sex-attractant pheromone
- MALE REPRODUCTIVE ORGANS IN VERTEBRATES:
- Testes: male gonads, contained in scrotal sacs
in mammals; correspond to labia majora in females. Seminiferous tubules
produce sperm; interstitial cells produce testosterone.
- Efferent ductules: carry sperm from testes to epididymis
- Epididymis: coiled tube that secretes much of seminal fluid
- Vas deferens (ductus deferens): carries sperm and seminal fluid
from testes to penis
- Seminal vesicles: secrete a thick, nutritive fluid containing
fructose, providing energy for the swimming motions of the sperm
- Prostate gland: secretes a thick, milky fluid containing enzymes
that help liquefy the seminal fluid after ejaculation
- Cowper's (bulbourethral) gland: secretes a clear fluid that
dilutes the seminal fluid and lubricates the urethra
- Male urethra: carries both urine and semen; made of 3 portions
(prostatic, membranous, penile)
- Penis: organ of copulation, corresponding to labia minora + clitoris
of female. Contains 3 bodies of erectile tisue: one corpus spongiosum
(corpus cavernosum urethrae) and two corpora cavernosa (corpora
cavernosa penis). All 3 become rigidly engorged with blood under
sexual stimulation. No penis exists in species where fertilization
is external.
|