Exam #1: Sex Differentiation

Front 1

What determines chromosomal sex?

Back 1

Whether the sperm fertilizing the ovum has an X or Y chromosome

Front 2

What must occur for the undifferentiated gonads to develop into testes?

Back 2

Must have a functional Y chromosome with an SRY gene which stimulates an autosome to produce H-Y antigen (which stimulates the medulla to develop into testes and the cortex to fade away)

Front 3

What must occur for the undifferentiated gonads to develop into ovaries?

Back 3

1. Must have migration of the primordial germ cells to the undifferentiated gonad and
2. the absence of a functional Y chromosome and
3. the presence of at least 2 functional X chromosomes- (the medulla fades away and the cortex develops into ovaries)

Front 4

What happenes if the PGCs do not migrate?

Back 4

1. In the XX individual, the gonads will remain in the undifferentiated state, or become gonadal streaks.
2. In the XY individual, testes will develop (assuming the other conditions are all met).

Front 5

What must be present for the male internal genitalia to develop?

Back 5

1. Androgens, Mullerian Inhibiting Factor and Inductor Substance
2. Wolffian ducts develop into the epididymus, vas deferens, and seminal vesicle, and the Mullerian ducts recede

Front 6

What must be present for the female internal genitalia to develop?

Back 6

1. Absence of androgens,
2. Absence of Mullerian Inhibiting Factor and
3. Absence of Inductor Substance
4. Mullerian ducts develop into oviducts, uterus, and vagina, and Wolffian ducts recede

Front 7

What are the three terms for the first half of the menstrual cycle?

Back 7

1. Proliferative phase (watch out this is not accurate)
2. preovulatory phase and
3. follicular phase

Front 8

When does the proliferative phase start? End??

Back 8

It starts at the END OF MENSES and ends at ovulation

Front 9

What factor(s) must be met for male external genitalia to develop?

Back 9

Presence of androgens

Front 10

What factor(s) must be met for female external genitalia to develop?

Back 10

Absence of androgens

Front 11

Name the three undifferentiated structures of external genitalia and what they form with differentiation in MALES

Back 11

1. Uro-genital fold=urethra
2. Genital tubercle= penis
3. Labio-scrotal swelling= scrotum (scrotal sac)

Front 12

Name the 3 undifferentiated structures of external genitalia and what they form with differentiation in FEMALES

Back 12

1.Uro-genital fold=labia minora
2. Genital tubercle=clitoris
3. Labio-scrotal swelling= labia majora

Front 13

What are the two structures that make up the undifferentialed gonad?

Back 13

The medulla and the cortex

Front 14

What does bipotentiallity of sex differentiation mean?

Back 14

1. Outcomes of earlier stages do not necessarily determine the direction of development at subsequent states.
2. Raw materials to develop in either direction are available at each stage.

Front 15

What is the sex chromosome complement of an inidividual with Turner Syndrome?

Back 15

XO

Front 16

Do individuals with Turner Syndrome have functional gonads?

Back 16

No, they are infertile

Front 17

When do gonads begin to sex differentiate?

Back 17

6 weeks after conception

Front 18

What structures makes up the internal genitalia of males?

Back 18

1. Epidiymis
2. Vas Deferens
3. Seminal Veslicles
4. Ejaculatory ducts and tubes

Front 19

What structures make up the internal genitialia of females?

Back 19

1. Uterus
2. Oviducts
3. Vagina