Flashcards in Module 11.1 Deck (39)
Which three hormones have been shown to promote maternal behavior in birds and mammals?
Estradiol, prolactic, and oxytocin
What is the SRY gene?
gene on the Y chromosome in males that causes gonads to turn into testes
What are Mullerian ducts?
precursors to female's oviducts, uterus, and upper vagina
What are Wolffian ducts?
precursors for some male reproductive organs
What are the three main sex hormones?
The estrogens, progesterone, and the androgens
What is the pudendal nerve?
it transmits tactile stimulation from the pubic area to the brain
How do the three main sex hormones exert their effect?
They are released mostly by the gonads and some by the adrenal glands
Distinguish between organizing and activating effects of hormones.
Organizing effects of hormones occur before birth and they determine if an individual will be male or female. Activating effects can occur at any time in life when a hormone temporarily activates a particular response.
Describe the chain of events that results from the presence of SRY during development.
The SRY gene causes the gonads to develop into testes. The testes produce testosterone, which increases the growth of testes, causing them to produce more testosterone and so forth. Testosterone also causes the Wolffian ducts to develop.
Describe the effects of testosterone injections on female rats during the last few days before birth and the first few days after birth.
Her body is partly masculinized, as if her body had produced the testosterone. Her clitoris grows larfer than normal, her behavior is partly masculinized, she approaches sexually receptive females
What happens to a mammal that is exposed to neither androgens or estrogens early in life?
they develop female anatomy
By what mechanisms does testosterone exert its effects on the hypothalamus in rodents?
The hypothalamus is masculinized
What are two sex differences in the structure and function of the hypothalamus?
The sexually dimorphic nucleus is larger in the male than in the female and contributes to the control of male sexual behavior. The hypothalamus in females can generate a cyclic pattern of hormone release, the male hypothalamus cannot.
What is the role of alpha-fetoprotein?
it binds with estradiol and prevents it from affecting the fetus
Which hormones can restore male-typical sexual behavior following castration?
What are estrogen's effects of the pudendal nerve's function?
estrogen increases it's sensitivity
What brain areas may facilitate male-typical behavior in males?
Ventromedial nucleus, the medial preoptic area (MPOA), and the anterior hypothalamus (sexually dimorphic nucleus-SDN)
What neurotransmitter in the MPOA stimulates male sexual activity?
How does castration affect the release of dopamine?
Castrated males produce normal amounts of dopamine, but do not release it
How do antidepressant drugs that increase serotonin decrease sexual arousal and orgasm.
serotonin inhibits dopamine, which stimulates male sexual activity
Describe the relationship between testosterone levels and sexual activity in men.
Testosterone is associated with the amount of sexual activity in men.
How does Viagra work?
itprolongs the effect of nitric oxide, which is necessary for erection
What are the two functions of the follicle
nurtures the ovum and produces several types of estrogen
Rising levels of which hormone cause a sudden surge of LH and FSH near the middle of the cycle?
What is the effect of the surge on the follicle/ovum?
causes an ovum to be released
What is the corpus luteum?
the remnant of the follicle after the ovum is released
What hormone does the corpus luteum release?
What are the effects of progesterone?
it prepares the uterus for implantation of a fertilized ovum and inhibits release of LH
Describe the levels of major hormones shortly before menstruation.
The levels of major hormones (estradiol, progesterone, LH, and FSH) decline shortly before menstruation
How do combination birth control pills work?
They prevent the body from releasing an ovum, thicken the mucus of the cervix (making it harder for sperm to reach the egg), and prevents an ovum from implanting in the uterus.
LIst the chain of hormonal event sin the menstrual cycle.
1. FSH released from pituitary causes follicle to develop.
2. The follicle builds up FSH receptors, so FSH effects increase and causes follicle to produce more estradiol. When estradiol reaches high levels, pituitary sends surge of FSH & LH that causes the follicle to break open and release the egg.
3. The corpus luteum releases progesterone, which prepares the uterus for implantation of a fertilized ovum. If the ovum isn't fertilized, the lining is cast off and this causes the period.
Describe the effects of a woman's menstrual cycle on their sexual interest and preferences for masculinized vs. feminized faces and athletic, competitive men.
Women who were in their periovulatory period preferred more masculine-looking faces and those who seemed athletic and assertive more than women in other phases of the menstrual cycle.
What are the four effects of oxytocin?
involved in contractions during birth, milk letdown, and orgasm, important for pair bonding and mother/infant bonding.
Which area is important for the hormones that promote parental behavior?
medial preoptic area and anterior hypothalamus
Describe the role of hormones and experience in the parental behavior of rats.
Hormones are important at first, but experience becomes more important as time goes on.
Describe LeVay's evidence implicating intersitial nucleus 3 of the hypothalamus.
LeVay found that the mean volume of INAH-3 was larger in heterosexual men than in heterosexual women or homosexual me.
What are three brain structures that show a sex difference in size?
anterior commissure, SCN, and INAH-3
How do homosexual men compare with heterosexual men and women in the size of the brain structures?
The anterior commissure is larger in women than in men. In homosexual men, it is at least as large as women's. The SCN is larger in homosexual men than in heterosexual men. The INAH-3 is more than twice as large in heterosexual men as in women and homosexual men.