exam two (ch.17) Flashcards
X chromosome contains ___ genes comparatively Y has ___ genes
800; 50
the sex determining gene is located on the y chromosome and is called
SRY gene
the SRY gene encodes testis-determining factor which is responsible for
development of testes and testicular hormones
Female development
is the “default”, but in response to ______, male development
takes place in both the genitalia and the brain
testosterone
during the first 6 weeks of development the sex is ___
undifferentiated
Female development
is the “default”, but in response to _____, male development
takes place in both the genitalia and the brain
testosterone
presense of SRY gene what duct is formed for males
wolffian
without the SRY gene what duct is developed in female s
mullerian
xxy
klinefelter (male)
XO
turner syndrome (female)
sex hormones are steriods derived from
cholesterol
male hormones
androgens
female hormones
progestins and estrogens
____ catalyzes the conversion of androgen (testoterone) to estrogen
aromatase
testes release what
androgen
testosterone surge at puberty leads to _____ of male reproductive system
maturation
ovaries secrete ___ and ____
estrogen and progesterone
male blood conc. of sex hormones fluctuate over a _____
24 hour period
females blood conc. of sex hormones fluctuate over ____
28 day cycle
_____ is highest during follicular phase
estrogen
____ is highest during luteal phase
progesterone
release of GnRH from the ___ ____ __ is influenced by light, psychological and sensory input
medial preoptic area (hypothalamus)
release of GnRH causes release of ___ and ___ from anterior pituitary
LH and FSH
in males ___ stimulates testosterone and ___ aids in sperm maturation
LH, FSH
in females ___ and ___ causes estrogens timing of menstrual cycle
LH and FSH
hormone secreted by pineal gland by dark phase of day-night cycle; inhibits gonadotropin release
melatonin
system responsible for releasing NT that relax smooth muscle in penis and clitoris
parasympathetic
system responsible for NT forcing muscular contractions in genitals
sympathetic
autonomic inputs and ___ ____ from the spinal cord influence response of penis and clitoris
sensory feedback (via dorsal column)
the parasympathetic inputs from the ___ spinal cord and increases blood flow to external sex organs
sacral
erotic thoughts and conscious control of sex organs is under _____ control
cortical
local spinal circuits coordinate cortical activity with sensory input from genitals are under ____ control
sub cortical (spinal cord)
male mates with many femals
polygyny
female mates with many males
polyandry
social and monogamous voles; lifelong partner bonds
prairie voles
the role of ___ and _____ receptors in the brain are a large part of social differences in the voles
oxytocin and vasopressin
the prairie voles have more or less receptors for vasopressin (male) and oxytocin (female)
more
during breastfeeding in mothers and during sexual intercourse in both men and women what increases
oxytocin (has role in human bonding)
the sexually dimorphic nucleus of rats is part of the ___ ___ __ and is larger in males than females
medial preoptic area
a sexual dimorphism of the CNS is humans is the ___ ____ of the anterior hypothalamus (INAH)
interstitial nuclei
the size of the anterior hypothalamic nuclei may correlate with ___ ___ in mammals
sexual preference
what part of brain may be smaller in homosexual males than heterosexual males
INAH-3
sexual dimorphisms of the CNS in humans is ___ ___ which is a collection of neurons innervating the base around the penis and vagina
onuf’s nucleus
masculinization vs. feminization of brain when it comes to the organization effects of hormones is ____
irrreversible
once testosterone enters a cell in female aromatase coverts to estrogen
alpha-fetoprotein in blood of fetal rodents prevents estrogen (estrodiol) from entering neurons (in both sexes) protecting female fetus from ____
masculinization
COX inhibitors, inhbit what
prostaglandin synthesis
COX inhibitor causes ____ copulatory behavior in male rats but increased male-like copulatory behavior in ____ rats
reduces; female
abnormally large adrenal glands overproduce androgens; don’t develop testes (tomboy behavior; low fertility)
Congenital adrenal hyperplasia
CAH
Experimentally delivering abnormally elevated testosterone during
early development _____ female reproductive behaviors in adult
genetic females
reduces
defective andrgen receptor gene which is carried on X chromosome; develop normal testes but they remain undescended in the abdomen; produce testosterone but not sensitive to it (appear female with external female genitalia)
androgen insensitivity in human genetic males (XY)
having both
male and female tissues
gynandromorph
the activational effects of sex hormones can temporarily change what two things
brain organization and behavior (animals)
ex. of activational effects of sex hormones
males: anticipation of sex: rise in testosterone; fall of test. is associated with
decreased sexual interest
direct or indirect affect of sex hormones
this method can alter membrane excitability and sensitivity to neurotransmitters and change neurotransmitter
release;
goal is to modulate functions of various enzymes, channels quickly
direct
direct or indirect affect of sex hormones
diffuse across outer cell membrane,
bind to specific steroid receptors in
cytoplasm and nucleus
goal is to alter gene expression; takes more time (slower)
indirect
Removal of ovaries _____ female
sexual behavior
reduces
for female the conc. of sex hormones in the ___ ____ of the hypothalamus effects sexual behavior
ventromedial nucleus
a lesion in the ventromedial nucleus blocks ____ in female rats (VMH projects to spinal cord; motor control)
lordosis
____ has a protective feature for neurons (can protect from stroke and MS during pregnancy)
estrogen
Although leptin levels rise, hormonal
changes lead to hypothalamic
resistance to leptin – elevated hunger!
changes during pregnancy
interaction with offspring in males Density of dendritic spines increase in
prefrontal cortex and is Associated with
increased expression of ______ receptors
vasopressin
when it comes to sexual dimorphism there are larger differences in ____ than between ____
individuals; sexes
Chemicals that transmit messages from
one animal to another
Detected by vomeronasal organ
pheromones
estrus cycles stop when
groups of female mice are housed alone
together
lee-boot effect
estrus cycles restart in
synchrony when a group of female mice
are exposed to urine of male mouse
whitten effect
failure of pregnancy when a
recently impregnated female mouse is
exposed to a male other than the one with
which she mated
bruce effect
Detects nonvolatile chemicals
in urine, other compounds
Projects to accessory olfactory
bulb
vomeronasal organ
from the olfactory bulb the vomeronasal organ projects to the ____ which has connections to the VMH (females) and MPA (males)
amygdala
Lesions of accessory ___ ____ disrupt the Lee-Boot,
Whitten, and Bruce effects
olfactory bulb
who had these findings?
- Females who spent time together had synchronized menstrual cycles
- Exposure to male underarm sweat induced synchronization
- Females who spent time with males had shorter cycle
McClintock: menstrual cycles of college female s
Androstenol (from adrenal gland; sweat) placed on necklace had no effect on social
behavior of males, but ______ interactions of females with males
increased
Most human behaviors are not distinctly masculine or feminine; However, _____ demands sex-specific behaviors
reproduction
