Chapter 10 - Sexual behaviour Flashcards
a behaviour that has different forms or that occurs with different probabilities or under different circumstances in males and females
sexually dimorphic behaviour
a matue reproductive cell; a sperm or an egg
gamete
the X or Y chromosomes, which determine an organisms gender.
XX = female, XY=male
sex chromosomes
an ovary or testes
gonad
the gene on the y chromosome whose product instructs the undifferentiated fetal gonads to develop into testes
sry
the effect of a hormone on tissue differentiation and development
organizational effect of hormone
the effect of a hormone that occurs in the fully developed organism; may defend on the organism’s prior exposure to the organizational effects of hormones
activational effects
the embryonic precursors of the female internal sex organs
Mullerian system
the embryonic precursors of the male internal sex organs
Wolffian system
a peptide secreted by the fetal testes that inhibits the development of the mullerian system, which would otherwise become the female internal sex organs
anti-mullerian system
an effect of a hormone present of early in development that reduces or prevents the later development of anatomical or behavioral characteristics typical of females
defeminizing effect
a male sex steroid hormone. testosterone is the principal mammalian androgen
masculinzing effect
the principal androgen found in males
testosterone
an androgen, produced from testosterone through action of the enzyme 5a reductase
dihydrotestosterone
a condition caused by a congenital lack of functioning androgen receptors; in a person with XY sex chromosomes, causes the development of a female with testes but no internal sex organs
Androgen insensitivity syndrome
a condition caused by a congenital lack of anti-mullerian hormone receptors for this hormone; in males, causes development of both male and female internal sex organs
persistant mullerian duct syndrome
the presence of only one sex chromosome (an x chromosome); characterized by lack of ovaries but otherwise normal female sex organs and genitalia.
turner’s syndrome
a hypothalamic hormone that stimulates the anterior pituitary gland to secrete gonadotropic hormone
- starts onset of puberty (under control of kisspeptin)
GnRH
a hormone of the anterior pituitary gland that has stimulating effects on cells of the gonads
- stimulate the gonads to produce their hormones, which is responsible for sexual maturation
gonadotropic hormone
the hormone of the anteriour pituitary gland that causes development of an ovarian follicle and the maturation of an ovum
FSH
a hormone of the anterior pituitary that causes ovulation and development of the ovarian follicle into a corpus luteum.
- causes ovulation, follicle reptures, and releases ovum.
- ruptured follicle becomes a corpus luteum which produces estradoil and progesterone.
LH (leuteinizing hormone)
the principal estrogen of many mammals, including humans
estradoil
a class of sex hormones that cause maturation of the female genitalia, growth of breast tissue, and development of other physical features characteristic of females
estrogen
the female reproductive cycle of most primates; characterized by growth of the lining of the uterus, ovulation, development of a corpus luteum and menstruation
menstrual cycle
the female reproductive cycle of mammals other tan primates
estrous cycle
a cluster of epithelial cells surrounding an oocyte, which develops into an ovum
ovarian follicle
a cluster of cells that develops from the ovarian follicle after ovulation; secretes estradoil and progesterone
corpus leteum
a steroid hormone produced by the ovary that maintains the endometial lining of the uterus during the later part of the menstral cycle and during pregnancy; along with estradoil it promotes receptivity in female mammals with estrous cycle
- promotes pregnancy
progesterone
a period of time after a particular action during which that action cannot occur again
refractory period
the restorative effect of introducing a new female sex partner to a male that has apparently become “exhausted” by sexual activity
coolidge effect
a hormone secreted by the posterior pituitary gland; causes contraction of the smooth muscle of the milk ducts, the uterus, and the male ejaculatory system; also serves as a NT in the brain
oxytocin
a spinal sexual reflex seen in many four-legged female mammals; arching of the back in reponse to approach of a male or to touching the flanks, which elevates the hindquarters
lordosis
a chemical released by one animal that effects the behaviour of physiology of another animal; usually smelled or tasted
pheromones
the slowing and eventual cessation of estrous cycles in groups of female animals that are housed together; caused by a pheromone in animals urine; first observed in mice
lee-boot effect
the synchronization of menstral or estrous cycles of a group of females, which occurs only in the presence of a pheromone in a male’s urine
whitten effect
the earlier the onset of puberty seen in female animals that are housed with males; caused by pheromones in the male’s urine
vandenbergh effect
termination of pregnancy caused by the odor of a pheromone in the urine of a male other than the one that impregnated the female
bruce effect
a sensory organ that detects the presence of certain chemicals, especially when a liquid is actively sniffed; mediates the effects of some pheromones
VNO
a neural structure located in the main olfactory bulb that receives information from the VNO
accessory olfractory buld
a nucleus that receives olfractory information from the olfractory bulb and accessory olfactory bulb; involved in the effects of odors and pheromones on reproductive behaviour
medial nucleus of the amygdala
a condition characterized by hypersecretion of androgens by the adrenal cortex; in females, causes masculinisatioin of the external genitalia
CAH
females ovaries produce
ova estradoil (estrogens)
male testes produce
sperm cells
androgens (testosterone)
produced by neurons in the arcuate nucleus (hypothalamus).
- essential for initiation of puberty and maintenance of male and female reproductive ability
kisspeptin
estadoil in females
breast development, growth of lining of uterus, changes in deposition of body fat, maturation of female genitalia
androgens in males
stimulate growth of facial hair, underarm, and pubic hair, lower the voice, alter hairline on head, stimulate muscular development, genital growth
entry of penis into vagina
intromission
discharge of seman
pelvic thrusting
sequence of estradiol followed by progesterone has 3 effects on female rats
1) receptivity
- ability and willingness to copulate
2) proceptivity
- eagerness to copulate
3) Attractiveness
- psycholigcal and behavioural chanes that affect the male (odor and her behaviour)
effects of pheromones
AOM sends axons to medial nucleus of amygdala (MeA) projects to anterior and ventromedial nucleus of hypothalamus.
adrenal glands secrete abnormal amounts of androgen’s
prenatal masculinization
boys normal - girls enlarged clitoris
CAH
birth of a boy with normal teste by lack of penis
cloacal exstrophy
sexually dimorphic region of hypothalamus, anteriour commissure
- within MPA
- larger in males than in females
- controlled by amount of androgens during fetal development
- critical period 18th day of gestation
- lesions decrase masculine sexual behaviour
SDN
BNST
larger in males than females
male-to-female transsexuals, BNST is same size as females
female-to-male transexualds, BNST is the same size as in males
size of BNST was as large in male homosexuals as in male heterosexuals
- size related to sexual identity, not sexual orientation.
unicatie nucleus of hypothalamus (medial preoptic area in rats)
twice as large in males than females
size in male-to-female transsexuals is about the same as that of females (similar to BNST)
neurons in the unicate nucleus send project to
BNST
- neural circuity that affects a person’s sexual identity
medial preoptic area
gets input from OB and AOB
- lesions abolish sex behaviour in male rodents
- mediates effects of pheromones on male sex behaviour
- recieves input from MeA and BNST
- recieves somatosensory information from genitals through connections with CTF (central tegmental field) of the mid brain and MeA
MeA
one region in nucleus is 85% larger in males than females (lots of androgen receptors)
- destruction disrupts sexual behaviour
- rats with lesions took longer to mount receptive females and ejaculate
- mating increased production of Fos
- receives input from PAG and nPGi of medulla
- nPGi inhibits spinal cord reflexes (5-HT)
- MPA supresses inhibition by inhibiting PAG (excites nPGi)
Figure Male Sexual Behaviour
- tactile information from genitals of central tegmental field (CTF) mating causes Fos production
- CTF activate MA (destruction disrupts sex behaviour. mating causes Fos production)
- MA activates MPA (destory abolishes sex behaviours. prenatal stress reduces size of SDN decrease sex behaviour. mating produces Fos production)
- MPA activates nPGi of medulla (part of pathway between MPS and motor neurons of spinal cord - ejaculation/erection)
ventromedual nucleus of hypothalamus (VMH)
biltaeral lesions will not display lordosis
- stimulation facilitates female sex behaviour
- MeA projects to VMH
Figure female sexual behaviour
- tactile information from genitals activates VMH
- VMH activates MA
- VMH activates PAG of midbrain
- PAG activates reticular formation - activates lordosis
peptide in brain responsible for formation of pair bonds - plays bigger role in men
vasopressin
peptide responsible for formation of pair bonds - plays bigger role in females
- increases trust, relaxation, calmness, well-being
oxytocin
hormone of anteriour pituitary gland, necessary for milk production
prolactin
parental behaviours avoidance
aversion response that virgin females make toward odor of pups
- olfactory system inputs to MeA
- lesions of MeA abolish aversion of virgin females to pups
- MeA projects to anterior hypothalamus (AH) projects to PAG (avoidance response)
- MPA inhibits activity of AH-PAG
parental caring behaviours
MTA projects to VTA and retrorubral field of midbrain
- dopamengeric neurons in VTA project to NAC (responsible for motivation and reinforcement)
- NAC projects to ventral pallidum (basal ganglia) involved in control of motivated behaviours
