Sex differentiation

Question 1

XX genes

Answer 1

female

Question 2

XY genes

Answer 2

Male

Question 3

on Y chromosome, turns
on testis-specific genes

Answer 3

SRY gene

Question 4

Regardless of its chromosomal makeup, the early embryo is blank, it has the potential to form either testes or ovaries

Answer 4

bipotential (gonadal sex)

Question 5

Which cells produce testosterone?

Answer 5

Leydig

Question 6

Which cells produce produce Anti-
Müllerian Hormone

Answer 6

sertoli cells

Question 7

sex organ that produces hormones

Answer 7

testes

Question 8

fairly inactive; don’t
produce significant amounts of
hormones until puberty.

Answer 8

ovaries

Question 9

How many surges of testosterone are there for babies, when do they happen and what do they affect.

Answer 9

2 surges.

first one is around 16 weeks after conception and influences reproductive morphology

second surge is around 8 weeks after birth and this affects the brain and reproductive behaviors

Question 10

What stimulates the secretion of testosterone during the first trimester of gestation

Answer 10

human chorionic
gonadotropin (hCG)

Question 11

produced by the placenta to maintain the pregnancy and stimulate steroidogenesis before the HPG axis is active

Answer 11

human chorionic
gonadotropin (hCG)

Question 12

Once the gonad has differentiated, differences in hormone
secretions direct morphological changes – starting with the

Answer 12

internal duct system

Question 13

With no hormones, the Müllerian ducts develop and the Wolffian ducts
undergo programmed cell death leading to the creation of

Answer 13

ovaries

Question 14

develop into the fallopian tubes, uterus, and cervix.

Answer 14

Müllerian ducts

Question 15

Leydig cells produce testosterone that binds to
androgen receptors and prevents regression of the
Wolffian duct - this becomes the

Answer 15

as deferens and
seminal vesicles.

Question 16

Sertoli cells produce Anti-Müllerian Hormone (AMH)
which causes the Müllerian duct to

Answer 16

regress

Question 17

Founder of modern fetal endocrinology

Answer 17

Alfred Jost

Question 18

used fetal rabbits at an early, ambivalent stage to explore the role of
hormones in sexual differentiation

Answer 18

Alfred Jost

Question 19

differentiates into
the glans of the penis

Answer 19

genital tubercle

Question 20

Develops into the scrotum

Answer 20

abioscrotal swellings

Question 21

Testosterone is converted to dihydrotestosterone (DHT) by the
enzyme

Answer 21

5α-reductase

Question 22

a more potent androgen - it binds to the androgen receptor with a much
stronger affinity

Answer 22

DHT

Question 23

responsible for External Morphological Sex

Answer 23

DHT

Question 24

Internal morphology is dependent on

Answer 24

testosterone

Question 25

External genitalia requires

Answer 25

DHT

Question 26

Mutation in AMH gene Develop both Wolffian and Müllerian ducts XY individual with stereotypical male genitalia, but they also have fallopian tubes and a uterus

Answer 26

Persistent Müllerian Duct Syndrome

Question 27

Can’t convert testosterone into DHT XY individual with testes and external female genitalia...until puberty

Answer 27

5α-reductase deficiency

Question 28

the most prevalent cause of intersex among people with XX chromosomes Adrenal glands lack CYP21A2 and do not make cortisol or aldosterone, instead overproducing androgens XX individuals with ambiguous genitalia

Answer 28

Congenital Adrenal Hyperplasia (CAH)

Question 29

the most prevalent cause of intersex among people with XY chromosomes Testosterone is produced but they can’t respond to it (lack functional androgen receptors)

Answer 29

Androgen Insufficiency Syndrome (AIS)

Question 30

Have rudimentary (undescended/internal) testes, but develop female external anatomy Testosterone is converted to estrogen

Answer 30

Androgen Insufficiency Syndrome (AIS)

Question 31

Are most behaviors sex specific?

Answer 31

no

Question 32

Sex differences in the brain are not uniformly different in any one individual

Answer 32

The Mosaic Brain

Question 33

Your blank continually shapes your brain

Answer 33

environment

Question 34

a region within the hypothalamus. It’s the best characterized sex difference in the mammalian brain (although this difference diminishes with age)

Answer 34

Sexually-dimorphic nucleus of the preoptic area (SDN-POA)

Question 35

a region within the hypothalamus. Larger in females than in males. Regulates ovulatory cycles.

Answer 35

Anteroventral periventricular nucleus (AVPV)

Question 36

When does the brain develop in reference to the gonads

Answer 36

The brain develops after the gonads

Question 37

organizes the brain during critical sensitive periods, and activates it at puberty and throughout adulthood

Answer 37

testosterone

Question 38

long-term and irreversible effects on tissues that occur during critical sensitive windows.

Answer 38

Organizational effects

Question 39

short-term and reversible effects that occur in adulthood (after puberty). Transient effects of hormones on the previously organized system.

Answer 39

Activational effects

Question 40

First evidence that hormones permanently shape the brain and later behaviors. It also provided the framework for discriminating two types of actions of gonadal steroids: organizational and activational.

Answer 40

Phoenix et al. 1959 Organizational vs Activational Experiments

Question 41

main finding of Organizational and Activational Effects in Males

Answer 41

Early surge of testosterone shaped (or organized) later behavioral responses activated by testosterone

Question 42

Main finding of Organizational and Activational Effects in Females

Answer 42

Testosterone surge at a critical period in brain development produces a “male” brain, and the absence of that hormone during the critical period produces a “female” brain.

Question 43

organizes’ the SDN-POA

Answer 43

testosterone

Question 44

what mascinulizes the brain?

Answer 44

estrogen

Question 45

Aromatization Hypothesis:

Answer 45

Developmental expression of aromatase in certain brain regions at critical time windows is required for organizational effects of testosterone.

Question 46

Testosterone can be converted to:

Answer 46

* estrogen via aromatase * dihydrotestosterone (DHT) via 5α-reductase

Question 47

How does estrogen cause size differences in these brain regions?

Answer 47

In the SDN-POA, estrogen promotes cell survival but in the nearby AVPV it induces cell death

Question 48

Only testosterone that has been converted to estrogen in the brain plays a role in sexual differentiation. true or false

Answer 48

true

Question 49

High levels of estrogen produced by the mother is prevented from affecting the offspring due to

Answer 49

Alpha-fetoprotein (AFP)