Question 1

In sensitive species, female fetuses are protected from the masculinizing effects of their mother's estradiol by

Accepted Answer

Alpha fetoprotein is a protein produced by the fetal liver that binds to estradiol and prevents it from crossing the blood-brain barrier and masculinizing the developing female brain. This is known as the alpha fetoprotein hypothesis.

Question 2

Which of the following statements about brain differentiation is true according to recent findings?

Accepted Answer

Recent findings show that brain differentiation is much more complex than previously thought, and that there is no single mechanism or hormone that accounts for all the differences between male and female brains. Genes, hormones, and environmental factors all contribute to the differentiation process, and the exact mechanisms are still being studied. Therefore, option A and B are incorrect. Option C is also incorrect as there is no such single mechanism that has been discovered till now.

Question 3

At puberty, in general feminization of the body

Accepted Answer

At puberty, feminization of the body is stimulated by a high ratio of estrogens to androgens. This is because estrogen promotes the development of female secondary sexual characteristics such as breast development, widening of the hips, and redistribution of body fat. Androgens such as testosterone, on the other hand, promote the development of male secondary sexual characteristics such as facial and body hair growth and a deepening voice. If androgens are present in high amounts or if estrogen levels are low, feminization of the body may not occur as fully or as rapidly.

Question 4

Ear wiggling

Accepted Answer

The answer of Ear wiggling
...

Question 5

Which of the following statements describes our current understanding of differences in the structure of human female and human male brains?

Accepted Answer

Many studies have documented structural differences between male and female brains, such as differences in cortical thickness and white matter connectivity. However, it should be noted that there is still debate in the scientific community over the significance and interpretation of these differences.

Question 6

If the testes of a normal male fetus were removed as soon as they developed, the child would be born with

Accepted Answer

The removal of testes in a male fetus would lead to a lack of testosterone and anti-Müllerian hormone, which are crucial for the development of male internal and external reproductive structures and the suppression of female duct development. Without these hormones, the fetus would not develop male reproductive structures, could potentially develop female internal reproductive ducts, and the hypothalamus might default to a pattern of releasing gonadotropin-releasing hormones cyclically, similar to the female pattern.

Question 7

The male and female external reproductive organs develop from the

Accepted Answer

The male and female external reproductive organs, including the penis and clitoris, develop from the same bipotential precursor during embryonic development. It is the presence or absence of certain hormones that determine the differentiation into male or female genitalia. The development of the internal reproductive organs, such as the testes and ovaries, is determined by the activation of either the Wolffian or Müllerian system, respectively.

Question 8

Brains of men and women exhibit the following general difference: Men's brains tend to be

Accepted Answer

The answer of Brains of men and women exhibit the...

Question 9

Alpha fetoprotein

Accepted Answer

Alpha fetoprotein (AFP) is present in the blood of neonatal rats, does not readily penetrate the blood-brain barrier, and deactivates circulating estradiol, making all of the given statements correct.

Question 10

In the evaluation of the effects of various hormone treatments on reproductive behavior, it is important to distinguish between "feminize" and "demasculinize" because they

Accepted Answer

Feminize and demasculinize do not always go together because they refer to separate aspects of reproductive behavior. Feminize refers to increasing or enhancing female-typical behaviors, while demasculinize refers to decreasing or inhibiting male-typical behaviors. It is possible for a hormone treatment to increase female-typical behaviors without necessarily decreasing male-typical behaviors, or vice versa. Therefore, it is important to distinguish between the two terms when evaluating the effects of hormone treatments on reproductive behavior. Option A is incorrect because feminize and demasculinize are not the same. Option B is partially correct in that both terms are opposite to masculinize and defeminize, but this does not fully capture their distinction. Option D is incorrect because not all choices listed are true. Option E is incorrect because although both terms are opposite to masculinize and defeminize, they are not the same.

Question 11

Which of the following male structures develops from the same fetal tissue as do the labia majora?

Accepted Answer

The labia majora and scrotum both develop from the same fetal tissue known as the genital tubercle. During development, the genital tubercle differentiates into male or female structures depending on the presence or absence of testosterone. In the absence of testosterone, the genital tubercle develops into the clitoris and labia majora in females. In males, testosterone causes the genital tubercle to differentiate into the penis and scrotum. Therefore, A) scrotum is the best choice as it is the only option that is a male structure and develops from the same tissue as the labia majora.

Question 12

There is good evidence in some species that testosterone does not masculinize the brain directly, that it is first converted to estradiol, which then masculinizes the brain.This hypothesis is called the __________ hypothesis.

Accepted Answer

The hypothesis that testosterone is first converted to estradiol, which then masculinizes the brain is called the aromatization hypothesis.

Question 13

At puberty, the growth of female pubic hair and axillary hair is stimulated by

Accepted Answer

The answer of At puberty, the growth of female pubic...

Question 14

Puberty is associated with an increase in the release of

Accepted Answer

During puberty, there is an increase in the release of growth hormone, adrenocorticotropic hormone (which stimulates the adrenal glands), and gonadotropic hormones (which stimulate the gonads), making all of the above correct.

Question 15

All gonadal sex hormones are

Accepted Answer

Gonadal sex hormones, such as testosterone and estrogen, are all steroid hormones that are derived from cholesterol. Therefore, choices A and C are both correct, making option D the best choice. Peptides, which are composed of amino acids, are not the main type of sex hormone.

Question 16

Which of the following is a secondary sex characteristic that is induced by an androgen other than testosterone?

Accepted Answer

The female pattern of pubic hair growth is induced by androgens other than testosterone, specifically dihydrotestosterone (DHT). DHT is a derivative of testosterone and is responsible for the masculinization of external genitalia in males and the development of the female pubic hair pattern in females. The other options (chest hair, increased muscularity, male pattern pubic hair growth, breasts) are all directly induced by testosterone.

Question 17

A normal genetic female who receives injections of testosterone throughout fetal development will be born with

Accepted Answer

The answer of A normal genetic female who receives injections...

Question 18

The external reproductive organs of males and females develop

Accepted Answer

The external reproductive organs of males and females develop from the same bipotential tissue, which means that both male and female structures are present in the early stages of development. The presence or absence of certain hormones determines which structures will develop further and become more prominent. Therefore, the development of external reproductive organs is not solely under direct genetic or estrogenic control, but rather a combination of various factors.

Question 19

A century and a half ago, puberty usually began at about __________ years of age.

Accepted Answer

The answer of A century and a half ago, puberty...

Question 20

The aromatization hypothesis is that

Accepted Answer

The aromatization hypothesis proposes that estradiol synthesized in the brain from circulating testosterone plays a crucial role in the development of sex-specific neural circuits associated with sexual behavior and other gender-related traits. This hypothesis has been supported by studies of genetically male individuals who lack aromatase, the enzyme that converts testosterone to estradiol, and exhibit a range of feminized cognitive and behavioral features.

Quiz 13: Hormones and Sex