Chapter 4: Hormones and Chromosomes

Question 1

Endocrine Glands

Answer 1

Secrete hormones and are important to development of the sexes
-releasing hormones are produced by the hypothalamus to stimulate the pituitary gland which produces tropic hormones to stimulate the gonads
(endocrine glands release hormones, hypothalamus stimulates the pituitary gland which produces tropic hormones)

Question 2

Gonads secrete steroidal hormones which are related to reproductive functioning

Answer 2

• Androgens, most common is testosterone
  -Estrogens, most common is estradiol
• Progestins, most common is progesterone
  both males and females produce all three but in different proportions

Question 3

What are the stages of Sexual Dimorphism

Answer 3

• beginning at conception
• Genetic stage: inheritance of sex chromosomes
  X and Y
• Gonadal Stage: the development of reproductive organs
  -Hormonal Stage: androgens and estrogens, prenatally and pubertal

Question 4

Internal Reproductive System

Answer 4

about six weeks after conception
-the difference in timing (internal vs external) allows for the possibility of errors in developing either the male or female patterns

Question 5

When Does External Genitalia Develop

Answer 5

about 3 months into prenatal development

- the difference in timing allows for the possibility of errors in developing either the male or female patterns

Question 6

Internal Structures Related to reproduction

Answer 6

• women: ovaries, fallopian tubes, uterus, upper vagina

- Men: testes, prostate glands, seminal vesicles, vas deferens

Question 7

External Structures Related to Reproduction

Answer 7

Women: clitoris , labia, vaginal opening
Men: penis, scrotum

Question 8

Sexual Differentiation

Answer 8

Chromosomes

• 23 pairs normally
• ovum 23 and sperm cell 23
• pair 23 is critical because it is our sex chromosomes

Question 9

Development of Male and Female Physiology

Answer 9

within the first 6 weeks of development there are no differences between male and female embryos

• both sexes start with the same internal reproductive system, initially identical, both capable of developing into male or female
• gene on the y chromosome prompts development of the testes which produce androgens during prenatal development

Question 10

Wolffian System

Answer 10

• the capacity to develop according to the male pattern if exposed to androgrens

Question 11

Mullerian System

Answer 11

• the capacity to develop according to the female pattern if not exposed to androgens

Question 12

The Male Process of Developing Reproductive Organs

Answer 12

• Must have the presence of androgens
• androgens prompt the development of the wolffian system
• secretion of mullerian-inhibiting substance causes the mullerian system to degenerate
• gonads develop into testes

Question 13

The Female Process of Developing Reproductive Organs

Answer 13

• The absence of androgens allows the mullerian system to develop
• the wolffian system degenerates
• the gonads develop into ovaries

Question 14

Development of External Genitalia

Answer 14

• this process begins in the third month of prenatal development
• ANDROGENS ARE CRITICAL, the presence of androgens creates the male pattern
• no androgens= female pattern

Question 15

Brain size and gender differences

Answer 15

• proportion is similar to differences In body size

Question 16

Cerebral Hemisphere Differences in the sexes

Answer 16

-lateralization of function occurs
(left- language, speech)
(right- spatial abilities)
men have more lateralization than women for language and spatial abilities but not significant.

Question 17

Sexually Dimorphic Nucleus (SDN)

Answer 17

• potential sex difference in brain structure
• located in the hypothalamus
• the most prominent brain difference
• 2.5 times larger in men than in women
• functions in humans is not yet understood but may be relate to sexual behaviour and gender identity

Question 18

Primary Sexual Characteristics

Answer 18

• maturity of sexual organs

- reproductive maturity

Question 19

Secondary Sexual Characteristics

Answer 19

• physical features that reflect sexual maturation but are involved directly in reproduction

Question 20

Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH)

Answer 20

• released by the pituitary gland and stimulates the gonads to increase production of estrogens and androgens
• this results in the maturation of genitals and produces the menstrual cycle

Question 21

LH and FSH differ in what way

Answer 21

LH- causes follicle to rupture and release ovum, involved in the maturation of sperm

FSH- stimulates follicles to mature an ovum, involved in sperm production

Question 22

Errors in meiosis can alter the sex chromosomes

Answer 22

XO = Turner Syndrome
XXY= klinefelter syndrome

Question 23

Tuner Syndrome XO

Answer 23

• from error during meiosis
• missing chromosome
• appear female at birth (but their mullerian system has degenerated) meaning no functional ovaries
• no estrogen or puberty
• hormone supplements

Question 24

Klinefelter Syndrome XXY

Answer 24

• error during meiosis
• male internal and external genitalia
• small testes, usually sterile
• may develop breasts and a feminized body during puberty
• developmental disorders

Question 25

Sexual development problems related to prenatal hormone exposure

Answer 25

• congenital adrenal hyperplasia

- Androgen Insensitivity Syndrome

Question 26

Congenital Adrenal Hyperplasia (Adrenogenital Syndrome)

Answer 26

• related to prenatal hormone exposure
• caused by an increase in androgen production
• for XY males, typically few problems occur (during early puberty)
• for XX females, causes masculinization of external genitalia
• can be fixed with surgery (controversial)
• “Tomboy” but majority identify as female

Question 27

Androgen Insensitivity Syndrome

Answer 27

• related to prenatal hormone exposure
• affects chromosomal XY males
• androgen receptors do not work so there is no production of mullerian- inhibiting substance.
• external genitalia appear female but have undescended testes , no internal female genitalia
• not typically identified until puberty when they fail to reach menarche and do not grow pubic hair
• identify as female

Question 28

Intersexuality (Hermaphroditism)

Answer 28

• Disorder of Sexual Development
• restricted to individuals who have both ovarian and testicular tissue
• RARE only 60 cases In north america and europe in the last century

Question 29

5-Alpha-Reductase Deficiency

Answer 29

• Extremely rare
• affects XY males
• appear female at birth but ambiguous
• develop according to the male pattern during puberty, respond to androgens
• 60% developed male gender and 40% retained female gender

Question 30

Premenstrual Syndrome (PMS)

Answer 30

• negative emotional, cognitive and physical symptoms
• result of hormonal changes prior to menstruation
• difference between menstrual symptoms and emotional and cognitive symptoms
• no relationship between hormone levels and pms

Question 31

Pre-Menstrual Dysmorphic Disorder

Answer 31

-treated with antidepressants

Question 32

The relationship between testosterone and aggression in humans

Answer 32

• complex
• testosterone increases aggression (little support)
• aggression increases testosterone
• aggression and testosterone are mediated. either biological or social
• high testosterone linked to impulsivity (e.g. drugs and alcohol) and antisocial (lack of consideration for others)
• complex interaction of high testosterone, low cortisol and low serotonin

Question 33

Berdaches

Answer 33

Two-spirit

• not intersex and not homosexual
• native american

Question 34

Hijras

Answer 34

Third Sex in india

may be intersex