10. SEXUAL DEVELOPMENT

Question 1

What is sexual dimorphism?

Answer 1

The existence of two sexes, with differences in physical and behavioral traits.

Question 2

How is external sex defined in humans?

Answer 2

By the appearance of external genitalia at birth.

Question 3

What defines internal sex?

Answer 3

The internal reproductive organs.

Question 4

What is chromosomal sex?

Answer 4

Determined by XX (female) or XY (male) chromosomes.

Question 5

What are primary sexual characteristics?

Answer 5

Externally visible traits at birth (e.g., penis, scrotum, labia, vag

Question 6

What are secondary sexual characteristics?

Answer 6

Traits that emerge during puberty (e.g., breast development, body hair).

Question 7

What are examples of internal sexual differences?

Answer 7

Females: ovaries, fallopian tubes, uterus; Males: seminal vesicles, prostate.

Question 8

What is sexual behaviour?

Answer 8

Behaviours related to mate selection, courtship, and intercourse.

Question 9

Define sexual orientation.

Answer 9

Direction of sexual attraction: heterosexual, homosexual, or bisexual.

Question 10

What is sexual identity?

Answer 10

A person’s self-perception of their sex, which may not match their anatomy.

Question 11

What is transsexualism?

Answer 11

The belief one is trapped in the body of the other sex.

Question 12

What are sexually differentiated behaviours?

Answer 12

Behaviours typically associated with one sex (e.g., aggression, emotional skills).

Question 13

How is genetic sex determined?

Answer 13

By sperm carrying an X or Y chromosome.

Question 14

What are gametes?

Answer 14

Sex cells (sperm and ova) with 22 autosomes and 1 sex chromosome.

Question 15

What determines genetic sex in humans?

Answer 15

The sperm (X or Y) that fertilizes the ovum.

Question 16

What is a zygote?

Answer 16

A fertilized egg cell formed from gametes.

Question 17

How is sex determined in butterflies and moths?

Answer 17

Females are ZW (heterogametic), and males are ZZ.

Question 18

What are primordial gonads?

Answer 18

Early embryonic glands that can become ovaries or testes.

Question 19

What are Müllerian ducts?

Answer 19

Embryonic structures with potential to become female internal organs.

Question 20

What are Wolffian ducts?

Answer 20

Embryonic structures with potential to become male reproductive organs.

Question 21

What does the Sry gene do?

Answer 21

Triggers synthesis of Sry protein, leading to testis development in males.

Question 22

What does testosterone do in male development?

Answer 22

Promotes development of male internal/external genitalia.

Question 23

What is the function of AMH (anti-Müllerian hormone)?

Answer 23

Prevents development of female reproductive organs and aids testis descent.

Question 24

How does female development occur?

Answer 24

In absence of SRY gene/testosterone, Müllerian ducts develop into uterus, etc.

Question 25

Why do men have nipples?

Answer 25

Because all embryos initially follow the female developmental pathway.

Question 26

What are bipotential precursors?

Answer 26

Embryonic structures that can become either male or female genitalia.

Question 27

When do external genitalia begin to differentiate?

Answer 27

End of the second month of pregnancy.

Question 28

What is puberty?

Answer 28

A transition period marked by growth, fertility, and secondary sexual traits.

Question 29

What initiates puberty?

Answer 29

Likely internal and external cues, not fully understood.

Question 30

What is the HPG axis?

Answer 30

Hypothalamic-Pituitary-Gonadal axis regulating sexual maturation.

Question 31

What hormones regulate puberty?

Answer 31

GnRH, LH, and FSH (gonadotropins).

Question 32

What is androstenedione?

Answer 32

An androgen that promotes hair growth in females.

Question 33

What causes adult body odour during puberty?

Answer 33

Increased androgen levels altering fatty acid composition of sweat.

Question 34

What causes acne during puberty?

Answer 34

Increased secretion of sebum due to androgens.

Question 34

What are activational effects of hormones?

Answer 34

Puberty/adult interactions that activate sexual behaviours.

Question 35

How does testosterone affect male behaviour?

Answer 35

Increases sex drive, aggression, mood swings, and impulsivity.

Question 35

What does brain sexual differentiation involve?

Answer 35

Activation and organization of specific neural circuits during development.

Question 35

What is the aromatization hypothesis?

Answer 35

Estradiol converted from testosterone masculinizes the brain.

Question 35

What prevents female brains from masculinizing?

Answer 35

Alpha fetoprotein binds to estradiol, preventing its entry into the brain.

Question 35

What are organizational effects of hormones?

Answer 35

Prenatal influences that shape sexual brain structure.

Question 36

What is androgenic insensitivity syndrome?

Answer 36

XY individuals unresponsive to androgens; develop as phenotypic females.

Question 37

What is adrenogenital syndrome?

Answer 37

Excess adrenal androgens in genetic females, causing masculinization.