Module 11.1

Question 1

Which three hormones have been shown to promote maternal behavior in birds and mammals?

Answer 1

Estradiol, prolactic, and oxytocin

Question 2

What is the SRY gene?

Answer 2

gene on the Y chromosome in males that causes gonads to turn into testes

Question 3

What are Mullerian ducts?

Answer 3

precursors to female’s oviducts, uterus, and upper vagina

Question 4

What are Wolffian ducts?

Answer 4

precursors for some male reproductive organs

Question 5

What are the three main sex hormones?

Answer 5

The estrogens, progesterone, and the androgens

Question 6

What is the pudendal nerve?

Answer 6

it transmits tactile stimulation from the pubic area to the brain

Question 7

How do the three main sex hormones exert their effect?

Answer 7

They are released mostly by the gonads and some by the adrenal glands

Question 8

Distinguish between organizing and activating effects of hormones.

Answer 8

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.

Question 9

Describe the chain of events that results from the presence of SRY during development.

Answer 9

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.

Question 10

Describe the effects of testosterone injections on female rats during the last few days before birth and the first few days after birth.

Answer 10

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

Question 11

What happens to a mammal that is exposed to neither androgens or estrogens early in life?

Answer 11

they develop female anatomy

Question 12

By what mechanisms does testosterone exert its effects on the hypothalamus in rodents?

Answer 12

The hypothalamus is masculinized

Question 13

What are two sex differences in the structure and function of the hypothalamus?

Answer 13

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.

Question 14

What is the role of alpha-fetoprotein?

Answer 14

it binds with estradiol and prevents it from affecting the fetus

Question 15

Which hormones can restore male-typical sexual behavior following castration?

Answer 15

testosterone

Question 16

What are estrogen’s effects of the pudendal nerve’s function?

Answer 16

estrogen increases it’s sensitivity

Question 17

What brain areas may facilitate male-typical behavior in males?

Answer 17

Ventromedial nucleus, the medial preoptic area (MPOA), and the anterior hypothalamus (sexually dimorphic nucleus-SDN)

Question 18

What neurotransmitter in the MPOA stimulates male sexual activity?

Answer 18

dopamine

Question 19

How does castration affect the release of dopamine?

Answer 19

Castrated males produce normal amounts of dopamine, but do not release it

Question 20

How do antidepressant drugs that increase serotonin decrease sexual arousal and orgasm.

Answer 20

serotonin inhibits dopamine, which stimulates male sexual activity

Question 21

Describe the relationship between testosterone levels and sexual activity in men.

Answer 21

Testosterone is associated with the amount of sexual activity in men.

Question 22

How does Viagra work?

Answer 22

itprolongs the effect of nitric oxide, which is necessary for erection

Question 23

What are the two functions of the follicle

Answer 23

nurtures the ovum and produces several types of estrogen

Question 24

Rising levels of which hormone cause a sudden surge of LH and FSH near the middle of the cycle?

Answer 24

Estradiol (estrogen?)

Question 25

What is the effect of the surge on the follicle/ovum?

Answer 25

causes an ovum to be released

Question 26

What is the corpus luteum?

Answer 26

the remnant of the follicle after the ovum is released

Question 27

What hormone does the corpus luteum release?

Answer 27

progesterone

Question 28

What are the effects of progesterone?

Answer 28

it prepares the uterus for implantation of a fertilized ovum and inhibits release of LH

Question 29

Describe the levels of major hormones shortly before menstruation.

Answer 29

The levels of major hormones (estradiol, progesterone, LH, and FSH) decline shortly before menstruation

Question 30

How do combination birth control pills work?

Answer 30

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.

Question 31

LIst the chain of hormonal event sin the menstrual cycle.

Answer 31

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.

Question 32

Describe the effects of a woman’s menstrual cycle on their sexual interest and preferences for masculinized vs. feminized faces and athletic, competitive men.

Answer 32

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.

Question 33

What are the four effects of oxytocin?

Answer 33

involved in contractions during birth, milk letdown, and orgasm, important for pair bonding and mother/infant bonding.

Question 34

Which area is important for the hormones that promote parental behavior?

Answer 34

medial preoptic area and anterior hypothalamus

Question 35

Describe the role of hormones and experience in the parental behavior of rats.

Answer 35

Hormones are important at first, but experience becomes more important as time goes on.

Question 36

Describe LeVay’s evidence implicating intersitial nucleus 3 of the hypothalamus.

Answer 36

LeVay found that the mean volume of INAH-3 was larger in heterosexual men than in heterosexual women or homosexual me.

Question 37

What are three brain structures that show a sex difference in size?

Answer 37

anterior commissure, SCN, and INAH-3

Question 38

How do homosexual men compare with heterosexual men and women in the size of the brain structures?

Answer 38

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.

Question 39

Can hormone levels in adulthood account for sexual orientation? What is a more plausible hypothesis concerning hormonal influence on sexual orientation?

Answer 39

No, it is more likely that prenatal hormone level influences sexual orientation, such as low-testosterone.