Lecture 13 Flashcards
(43 cards)
proceptivity and the menstrual cycle in humans
female more likely to show initiation during ovulatory period and follicular period
in postmenopausal women estrogen replacement ___
increases libido
in naturally cycling women estrogen is positively associated with
- sexual desire
- sexual attraction to men other than one’s primary partner
female pacing of copulation
when female has control over when the intermissions occur during a mating test
in paced paired mating tests females return to the male…
more slowly following ejaculation compared with mounts or intromissions
what follows intromissions
prolactin release –> corpora lutea support –> enables implantation of the blastocyst
pacing and multiple intromissions
slower pacing of intromission in the paced test optimizes reproduction
what happens if the female doesn’t have significant number of intromissions?
the wall cannot build up and eggs cannot implant successfully
menstruation bleeding
- due to steroid deprivation
- occurs when E and P are at baseline
- without steroid support the endometrial layer sloughs off and blood vessels leak blood
what strengthens the uterine walls?
intromission stimulation of prolactin release
when do estrogen levels peak
at time of ovulation
why does progesterone peak later
due to formation of corpora lutea, continues to remain high during luteal phase, if pregnancy not achieved the progesterone levels drop off
proestrus bleeding
- due to steroid stimulation
- dogs/some other mammals discharge blood during proestrus
- due to estrogen-induced stimulation of the uterine wall causing rapid growth which tears blood vessels
induced ovulation in prairie voles
if a male is present
- anogenital investigation
- exposure to male urine
- VNO –> main olfactory bulb –> release of GnRH
- stimulates release of LH (possibly FSH) 1 hour post-exposure
- within 24 hours gonadotropin release has stimulated estrogen release and the onset of estrous behavior
- approx 12 hours following copulation, ovulation occurs
Lee-Boot effect
estrous cycle lengthens in all female mice when they all live together, female-released chemosensory cue that is released and detected by females leading to a longer estrous cycle
Bruce effect
pregnant females exposed to not-sire male for at least 2 days, presence of chemosensory cues from males cause GnRH release and behavioral estrus onset, females abort or resorb their fetuses
Whitten effect
chemosensory cues from male that impact female hormonal status, induces estrous behavior within 48 hours of introducing male into all female living environment, male urine causes GnRH release
Vandenbergh effect
juvenile female around grown male, earlier onset of puberty in females, females exposed to lots of adult females delays onset of cylce
pheromones and the human menstrual cycle
evidence for human pheromone release and detection among women, can impact the menstrual cycle of other women
results of female pheromone experiment
- women exposed to odors of women in follicular phase had a reduced length of cycle shortened by about 2 days
- women exposed to odors of women in ovulatory phase had an increased length of cycle by about 1.5 days
female pheromone experiment
- absorbent pads under arms for Dif stages of menstrual cycle
- experimenters took pads and froze them
- new cohort of women would rub frozen pads under noses
- new women exposed to pheromones released onto pads from first group of women
- looked at menstrual cycles of second group of women
stress and the menstrual cycle
high stress levels = irregular menstrual cycles, strong association between stress and dysmenorrhea
McClintock effect
study of undergraduate women living in dorms, menstrual synchronization more likely in roommates, took about 7-8 months of cohabitation before synchronicity occurred
nutrition and the menstrual cycle
both inadequate diet, or habitual hyper caloric food consumption affect ovarian function and decrease fertility
