Neuroscience of sex

Question 1

Sex

Answer 1

refers to a set of biological attributes in humans and animals.

Question 2

Gender

Answer 2

refers to the socially constructed roles, behaviours, expressions and identities of girls, women, boys, men, and gender diverse people.

Question 3

Who was Anton von Leeuwenhoek?

Answer 3

examined sperm and drew what he thought he saw…

Question 4

What determines the sex of the child?

Answer 4

the last of 23 pairs of chromosomes determines sex of the child.the

Question 5

females

Answer 5

XX

Question 6

Males

Answer 6

XY

Question 7

Y chromosome

Answer 7

not responsible for everything – it does control the development of glands producing male sex hormones.

Question 8

Sry

Answer 8

single gene called Sry on the Y chromosome produces testis -determining factor, which causes the formation of testicles.

Question 9

What is the default for humans?

Answer 9

default for humans is female if they don’t have SRY gene

Question 10

organization

Answer 10

permanent, influence brain and sex organ development. Effects occur during the early development of an animal.

Question 11

activation

Answer 11

effect of a hormone on a fully developed (adult) organism. Occurs later in life, after development of sex organs.

Question 12

Levels of sexual

Answer 12

Genes: XY or XX

Gonads: Testes or Ovaries

Internal Sex Organs: Wolffian System, Vas Deferens, Prostate or Mullerian System, Fallopian Tubes, Uterus

External Genitalia: Penis, Scrotum or Clitoris, Labia

Secondary Sex Traits: Body & Facial Hair, Muscle Mass or Body Hair, Breasts

Question 13

T.D.F =

Answer 13

testes determining factor

Question 14

Internal sex organs

Answer 14

Precursor of female internal sex organs (Mullerian system)

Precursor of male internal sex organs (Wolffian system)

1 promoted & 1 goes away

Question 15

The fight to be male!

Answer 15

sexual dimorphism becomes apparent ≈60 days after conception.

testosterone stimulates differentiation.

presence of hormones (HORMONES ANTIMULLERIAN AND ANDROGEN) will lead to development of internal sex organs that eventually leads to male sex organs

absence of hormones will lead to development of female organs.
b/c
default setting is female

Question 16

antiMullerian hormones

Answer 16

prevents female development

Question 17

androgen

Answer 17

stimulates Wolffian system for male development

Question 18

Androgen insensitivity syndrome

Answer 18

(an XY female) – lack of androgen receptors.
- can’t have children

external genitalia are female but internal female organs fail to develop (antiMullerian hormone still functions).

Question 19

Persistent Mullerian duct syndrome

Answer 19

(genetic males) – both male and female internal sex organs develop (failure to produce antiMullerian hormone or receptors).

• causes female precursor to die away
• in this case, there’s a failure so both internal systems will develop

Question 20

Congenital adrenal hyperplasia

Answer 20

– exposure of female fetus to androgens (can produce an enlarged clitoris, fused labia and tomboyish behaviour).

Question 21

CAH

Answer 21

Hydroxylase deficient congenital adrenal hyperplasmia. The patient was GENETICALLY FEMALE (XX), PHENOTYPICALLY & BEHAVIOURALLY MALE, & presented only as a problem of infertility with ‘ABSENT TESTES.’ Note short statue due to premature epiphyseal fusion.
- looks & acts male, but don’t have testicles

Question 22

Turner’s syndrome — monosomy

Answer 22

• 23rd pair of chromosomes isn’t a pair, it’s a single

(X0) - only 1 X chromosome

• fetus still develops into a female (the default setting hypothesis - evidence of that!)
• characterized by undeveloped ovaries but otherwise normal female sex organs & genitalia
• infertile
• short of stature, webbed neck

Question 23

Klinefelter syndrome

Answer 23

trisomy

XXY Males: testes do not develop as normal (remain small), which leads to infertility. Extra X comes from father just over ½ the time.

1/500 males

• extra chromosome on 23rd pair

Question 24

XYY

Answer 24

• “Super Male”
• tend to be more physically active as children.
• somewhat delayed emotional maturity.
• sexual development is normal.
• 1/1000 males
• everything of a male stereotypically exaggerated

Question 25

XXX

Answer 25

• “Super Female”
• quiet and passive as infants.
• delayed development in motor function, speech, and maturation.
• normal physical sexual development.
• normal-to-slightly diminished fertility.
• 1/1000 females
• everything of a female stereotypically exaggerated

Question 26

Sexual maturation

Answer 26

sex hormones

• estradiol (from ovaries).
• testosterone, androgen (from testes).
• a little of the opposite sex hormone is produced by each sex.

other effects of gonadal steroids

• halt skeletal growth. (after puberty, done growing by enlarge)
• estradiol (during puberty)
• androgens (during puberty)