Sex and stress

Question 1

According to Walter Cannon, what is the fight or flight response?

Answer 1

Evolutionary preparation for a threatening event.

Question 2

What happens physiologically during the fight or flight response?

Answer 2

1. Adrenal medulla secretes adrenaline and noradrenaline
   - this affects glucose metabolism, stored nutrients in muscles become available.
   - increases HR and BP
2. Adrenal cortex secretes cortisol
   - converts protein to glucose
   - makes fats available for energy
   - increases blood flow
   - increases behavioural responses (e.g. inhibits sex hormones)

Question 3

How are glucocorticoids like cortisol released and controlled?

Answer 3

1. PVN of hypothalamus secretes CRH (cortico-tropic releasing hormone), a peptide.
2. CRH stimulates the anterior pituitary gland to release ACTH.
3. ACTH enters circulation and stimulates adrenal cortex to release glucocorticoids
4. Negative feedback system to regulate.

Question 4

What are the effects of long term stress?

Answer 4

Poor health - more likely to get ill.

Question 5

What did Cohen (1953) find?

Answer 5

That survivors of concentration camps have poorer health in life later on.
- could be due to poor conditions and malnutrition?

Question 6

What did Theorell et al (1992) find about subway train drivers?

Answer 6

Those who accidentally injure or kill people are more likely to be ill months later.

Question 7

What did Selye (1976) attribute the health effects of long term stress to?

Answer 7

Glucocorticoids - increase BP, damage muscle tissue, increase infertility, suppress the immune system, increase steroid diabetes and inhibit growth.

Question 8

What are rats put in a cage next to a chamber containing a rat worse at?

Answer 8

Spatial navigation tasks.

Question 9

When is gender determined?

Answer 9

At fertilisation.

Question 10

What are the first sex organs to develop?

Answer 10

The testes/ovaries.

Question 11

What are the roles of the testes/ovaries?

Answer 11

• Produce sperm/ova

- Secrete hormones which determine sex organs and brain (organisation effects) and activation effects at puberty.

Question 12

Until what stage in pregnancy are foetuses undifferentiated?

Answer 12

The 6th week.

Question 13

What causes the gonads to become testes?

Answer 13

Sry (sex-determining region Y) gene on the Y chromosome.

Question 14

Why are females the default setting?

Answer 14

If nothing happen, female genitalia develop - something has to happen for testes to be formed.

Question 15

Until what stage in pregnancy does an embryo possess the precursors to both male and female sex organs?

Answer 15

Three months.

Question 16

What is the precursor to male sex organs called?

Answer 16

Wolffian system.

Question 17

What is the precursor to female sex organs called?

Answer 17

Mullerian system.

Question 18

How is it determined which precursory system withers?

Answer 18

In males, the testes secrete:

• Anti-Mullerian hormones (de-feminising)
• Androgens, e.g. testosterone (masculinising)

Question 19

What is androgen insensitivity syndrome (Money and Ehrhardt, 1972)?

Answer 19

• XY but mutation prevents formation of androgen receptors.

- Testes secrete A-M hormones and androgens but no masculinisation.

Question 20

What is persistent Mullerian duct syndrome (Warne and Zajac, 1998)?

Answer 20

• Caused by absence of AM hormone or receptors.

- In males, masculinising effect but no defeminisation so both sets of internal sex organs develop.

Question 21

What is Turner’s syndrome?

Answer 21

• X0 foetus.
• No Y chromosome therefore no testes, but XX needed for ovaries.
• Develop normal female internal and external genitalia but can’t have children.

Question 22

What is andrenogenital syndrome?

Answer 22

• Low levels of cortisol result in high levels of adrenal androgens.
• Early onset of puberty in males.
• In females causes enlarged clitoris and fused labia = ambiguous sex organs.

Question 23

How is external genitalia developed in males and females?

Answer 23

• No female hormones needed.

- In males, dependent on an androgen (hence Turner’s syndrome).

Question 24

When does sexual maturation occur?

Answer 24

When:

• Hypothalamus secretes GnRH
• Stimulates anterior pituitary gland to release gonadotrophic hormones
• Stimulates the gonads to produce their hormones (FSH and LH).

Question 25

What are the female gonadotrophic hormones?

Answer 25

• Follicle stimulating hormone (FSH)

- Luteinising hormone (LH)

Question 26

What do FSH and LH do?

Answer 26

• Produce follicles
• Enable luteinisation (menstruation)
• Ovaries secrete oestrogen

Question 27

What do gonadotrophic hormones in men do?

Answer 27

Stimulate testes to produce sperm and secrete testosterone.

Question 28

What do animal studies show about male hormonal control of sexual behaviour?

Answer 28

• Male rats nuzzle, sniff/lick and mount a receptive female, after 10 intromissions of 0.25s each male ejaculates.
• Refractory period - interval between successive ejaculations increases.
• Coolidge effect (Beamer et al., 1969) - introduction of a new female rejuvenates an exhausted male, which in rams is dependent on odour.

Question 29

What do animal studies show about female hormonal control of sexual behaviour?

Answer 29

• More passive role - move tail away, stand rigidly and raise hindquarters.
• Active role in initiation (McClintock and Adler, 1978) - quick, short hopping movements and ear wiggling.
• If unwilling will flee from or fight males attempting to copulate.

Question 30

What has been shown about human female hormonal control of sexual behaviour?

Answer 30

According to Van Goozen et al (1997), women will initiate sex more during ovulation when estradiol levels are high.

Question 31

What has been shown about human female hormonal control of sexual behaviour?

Answer 31

• Bagatell et al (1994) gave males placebo or a GnRH antagonist. GnRH group reported decreases in sexual interates, fantasies and intercourse. Effect removed by extra testosterone.
• Hellhammer et al (1985) found that watching an erotic film increased men’s testosterone.