Chapter Nine Flashcards
Reproductive behavior involves…
courting, mating, parental behavior, and aggressiveness
The three physical sex characteristics
genetics, gonads, genitals
How do the sperm and egg replicate?
meiosis; each gamete ends up with 23 chromosomes at fertilization, 23 + 23 = 46
What are the first 22 pairs of chromosomes?
autosomes
The egg is always the…
X chromosome
The sperm is…
either X or Y chromosome; determines sex of the baby
Genetic sex is either…
XX or XY
Gonadal sex is either…
ovaries or testes
Genital sex is either…
external sex organs of both male and female
The function of gonads
to produce gametes (ova or sperm) and to produce hormones which change your brain
SRY protein
in a male fetus–> testes
absent in female fetus–> ovaries
Hormones produced by the gonads do two things…
organizational effects (on brain and genitals) and activation effects (erection, ovulation)
Mullerian System
in females; embryonic precursor of female internal sex organs (uterus and fallopian tubes); no special hormone necessary for development
Wollfian System
in men; embryonic precursor of male internal sex organs (Vas deferens and seminal vesicles); special hormones needed–> anti-mullerian hormone and androgens
Anti-mullerian hormone
produced by the testes which prevent the female system from developing
Androgens
produced by the testes which promote the wollfian system
dihydrotestosterone
produces external sex organs in men
Androgen Insensitivity Syndrome
male; receptors are insensitive to androgens; female system turned off, but male system not promoted; external appearance of female, but genetically XY and gonadally a male (testes)
Turners Syndrome
born with only one sex chromosome (X or X0); with no Y chromosome, testes do not develop, and body of female follows; XX is needed to develop ovaries so those are not present either; have appearance of female but can not reproduce
primary sex characteristics
the changes necessary for reproduction- ova and sperm
secondary sex characteristics
changes not necessary for reproduction- body hair, deepening voice
process of secondary sex characteristics
hypothalamus –> gonadotropin releasing hormone –> anterior pituitary releases gonodotropic hormones (follicle stimulating hormone and lutenizing hormone) –> gonads release sex hormones (estradiol (female) and androgens (male)
Ovulation
pituitary –> FSH which stimulates growth of follicle, follicle –> estrodial which goes back up into pituitary and grows uterine lining and anterior pituitary –> LH –> ovulation: when egg is released from follicle
corpus luteum
an eggless follicle; already released the egg; releases progesterone and estrodial which promote pregnancy
menstrual cycle
month growth/loss of lining of uterus
estrous cycle
non-primates; takes 4 days
hormone regulation or sexual behavior in males determined by..
testosterone
castration cessation
take it away
injection resurgence
comes back
hormone regulation of sexual behavior in females determined by..
estradiol and progesterone
estradiol levels surge 40 hours prior…receptive progesterone levels peak
ovariectomy
causes cessation of behavior; proper sequence of estradiol causes progesterone resurgence and both need to be injected in the proper sequence
How can hormones reverse normal behavior?
castrate a male rat, when given estradiol and progesterone it displays female behavior
behavioral defeminization
prevent female sexual behaviors
behavior masculinization
promotes male sexual behaviors
pheromones
detected with olfactory system, many times below level of conscious awareness
Lee Boot effect
female mice house together have cycles slow down and stop
Written effect
if exposed to odor of a male, cycles will “restart”
Vandenbergh effect
odor of male will accelerate onset of puberty in female
Bruce effect
pregnancy will fail in mouse if she encounters a different male; if male is castrated, this does not occur
Vermonasal Organ
projects to the accessory olfactory bulb; lesions elimated all of the effects talked about; evidence its found in humans
olfactory synchronization
women spending time together end up with synchronized cycles; women spending more time in presence of males have shorter cycles than those who don’t; women exposed to “donor” sweat have cycles that synchronize with the donor
Garcia-Velasco & Mondragon (1991)
found an “organ” in nearly every 1,000 plastic surgery cases
Is sexual behavior tied to menstrual cycles?
no; this is the case in other non-human species
do women taking oral contraceptives have less deviation in sexual desire? or more?
less deviation
When do married couples have more sex and more satisfaction?
when wife’s testosterone levels are at their peak
What happens when testosterone is removed in men?
sperm production and desire stops; prior experience may determine how quickly sexual desire decreases when testosterone is removed
Of self-report data, how many people report homosexuality?
1-10%; no evidence of learning or changes in hormone levels
Congenital Adrenal Hyperplasia
adrenal glands secrete too many androgens; doesn’t affect males but females show much higher rates of homosexuality/bisexuality
Money et al. (1984)
reported rates near 40% with another 23% who didn’t want to discuss orientation (cognate adrenal hyperplasia)
Simon Levay
brain structure in hypothalamus differed in males and females; homosexual males = hetero females, vice versa
problems with sample and method
Bailey and Pillard (1991)
identical twins concordance rates or 52%; fraternal twins concordance rate- 22%
similar numbers when twins reported lesbianism; compared to 1-10% of general population this is dramatic increase
Medial preoptic area in parental behavior
lesions of MPA disrupt nest building/pup care in females with no disruption in sexual behavior; neurons of MPA are activated when maternal behavior occurs in female rodents; estradiol infused into MPA will facilitate maternal behavior in females; not often studied in males because many species do not get paternal involvement after birth
prarie voles
monogamous, shows paternal behavior
medial proptic area is same in males and females
meadow voles
promiscuous
very different size of medical preoptic area in males and females
