Lecture 1 - Introduction

Question 1

What is the chromosome pattern for females?

Answer 1

XX

Question 2

What is gender identity?

Answer 2

The sense of being male / female independent of genetic sex or physical appearance.

Question 3

Briefly explain the genetics of sex.

Answer 3

Mothers provide X chromosomes and fathers provide Y chromosomes.

Question 4

What are organisational effects of sex hormones?

Answer 4

• Organisational effects of sex hormones are effects that influence development from conception and sensitive periods.
• determine whether the brain develops as male/female
• Permanent

Question 5

What are activational effects of sex hormones?

Answer 5

Activational effects of sex hormones temporarily activate reproductive responses and behaviours

Question 6

When do organisational affects occur specifically ?

Answer 6

Sensitive periods such as:

• Conception
• 0-12 months
• Puberty

Question 7

When do activational effects of sex hormones occur?

Answer 7

Any time in life

Question 8

How long can activational effects of sex hormones last for on organs?

Answer 8

Up to months longer than the hormone is present

Question 9

How clear cut is the distinction between activational and organisational effects of sex hormones?

Answer 9

The distinction is not absolutely as the two may occur simultaneously. E.g. during puberty hormones can induce long lasting structural changes (organisational effects) as well as activating effects.

Question 10

In prenatal development, between 0-6 weeks, what type of gonads do females have?

A) wolffian ducts
B) Mullerian ducts
C) All of the above

Answer 10

C) All of the above

At 0-6 weeks the gonads of every male and female are identical, both have a set of Mullerian and Wolffian ducts.

Question 11

What does SRY stand for?

Answer 11

Sex determining Region on the Y Chromosome

Question 12

What happens at 6weeks onwards in the prenatal development in males?

Answer 12

The SRY gene kicks in, causing the primitives glands to develop into testes.

Question 13

What happens from 3months in the prenatal development of males?

Answer 13

• the developing testes produce testosterone
• testosterone promotes the development of the wolffian ducts which then develop into seminal vesicles and vas deferens
• anti-Mullerians cause the degeneration of Müllerian ducts stopping female development.

Question 14

Explain the organisational role of sex prenatally in females.

Answer 14

After six weeks in the absence of androgens, the woffian system degenerates and the female internal organs start to develop from the Mullerian system

Question 15

What are seminal vesicles?

Answer 15

Sack like structures that store semen

Question 16

What is the vas deferens?

Answer 16

A duct from the testicles to the penis

Question 17

What are secondary sex characteristics?

Answer 17

Changes that occur during puberty

Question 18

What does GnRH stand for?

Answer 18

Gonadtrapin Releasing Hormones

Question 19

What signals the onset of puberty and how?

Answer 19

Gonadtrapin releasing hormones (GnRH) are released by the hypothalamus.

Question 20

What two other hormones does GnRH stimulate and release?

Answer 20

1. Follicle Stimulating Hormones (FSH)

2. Lutenizing Horome (LH)

Question 21

Which hormone does the testes release during puberty to promote the development of secondary sex hormones?

Answer 21

Testosterone

Question 22

Which hormones does the ovaries release during puberty to promote the development of secondary sex hormones?

Answer 22

Estradiol

Question 23

Name four changes that occur in puberty as a result of androgens.

Answer 23

1. Muscular development
2. Maturity of external genitalia
3. Enlargement of Larynx - deeper voice
4. Affects to hairline - may lead to baldness in adulthood