bio lecture 1

Question 1

What is a gonad?

Answer 1

An organ that produces gametes (sex cells) and reproductive hormones.

Question 2

What are the two types of gonads?

Answer 2

Testes (Male Gonads) and Ovaries (Female Gonads).

Question 3

What do testes produce?

Answer 3

Sperm and secrete testosterone.

Question 4

What do ovaries produce?

Answer 4

Eggs (ova) and secrete oestrogen and progesterone.

Question 5

What chromosomes determine sex?

Answer 5

XX (female) and XY (male) chromosomes.

Question 6

What is the role of the SRY gene?

Answer 6

Activates testis development; absence results in ovary development.

Question 7

What hormones does the early testis produce?

Answer 7

Anti-Müllerian Hormone and Androgens.

Question 8

What does Anti-Müllerian Hormone do?

Answer 8

Defeminises by preventing female organ development.

Question 9

What do androgens cause?

Answer 9

Masculinisation, leading to the development of male traits.

Question 10

What are primary sexual characteristics in females?

Answer 10

Internal organs: uterus, fallopian tubes, and ovaries; External organs: vulva, clitoris, and vagina.

Question 11

What are primary sexual characteristics in males?

Answer 11

Internal organs: vas deferens, epididymis, prostate, and seminal vesicles; External organs: penis and scrotum.

Vas deferens:
A muscular tube that transports sperm from the epididymis

Question 12

What are organizational effects of hormones?

Answer 12

Effects that occur during critical periods and persist after hormone removal.

Question 13

What are activational effects of hormones?

Answer 13

Temporary effects that depend on hormone presence.

Question 14

What triggers the onset of puberty?

what do they do?

Answer 14

Kisspeptin and GnRH.
K= produced in hypothalamus and it stimulates the release of GnRH
GnRH= produced by the hypothalamus to signal pituitary gland to release LH and FSH

Question 15

What is the hypothalamo-pituitary-gonadal (HPG) axis?
explain process…

Answer 15

A negative feedback loop:

1. (kisspeptin, stress, puberty timing, and feedback from sex hormones) causes Hypothalamus to Releases GnRH
2. GnRH travels to pituitary glang and stimulates release of LH and FSH
3. LH and FSH travel in the bloodstream and tell the gonads to Make sex hormones and Produce gametes (sperm or eggs)

High levels of sex hormones send feedback to the brain to slow down GnRH, LH, and FSH.

Question 16

What initiates the HPG axis process?

Answer 16

kisspeptin

Question 17

What does the hypothalamus release in the HPG axis?

Answer 17

Gonadotropin-Releasing Hormone (GnRH).

Question 18

What hormones do the anterior pituitary release?

Answer 18

Luteinizing Hormone (LH) and Follicle-Stimulating Hormone (FSH).

Question 19

What do gonads produce in response to LH and FSH?

Answer 19

Testosterone (from testes) and Oestrogen/Progesterone (from ovaries).

Question 20

HPG Axis- how do hormones regulate menstrual cycle through HPG axis

Answer 20

Follicular Phase
ovulation
luteal phase

Question 21

What happens during the follicular phase of the menstrual cycle?

Answer 21

hypothalamus- GnRH- LH and FSH- FSH promotes follicle growth in the ovaries.- the developing follicle produces estradiol (a form of oestrogen)

Question 22

What triggers ovulation?

Answer 22

Rising estradiol levels - surge in LH- causes ovulation (egg is released from the follicle into the fallopian tube)

Question 23

What occurs during the luteal phase?

Answer 23

After ovulation, the empty follicle transforms into the corpus luteum- produces progesterone and oestrogen- if no pregnancy it degenerates after 2 weeks

Question 24

What happens if no fertilization occurs?

Answer 24

Progesterone and oestrogen levels drop, triggering menstruation.

Question 25

What is Androgen Insensitivity Syndrome (AIS)?

Answer 25

A condition where testosterone has no receptors to bind to, resulting in female anatomy despite XY chromosomes.

Question 26

What is 5α-Reductase Deficiency?

Answer 26

Inability to convert testosterone to DHT, leading to female external genitalia but male internal organs.

Question 27

What is Congenital Adrenal Hyperplasia (CAH)?

Answer 27

A condition causing excess prenatal testosterone in 46,XX individuals, leading to ambiguous genitalia and masculine traits.

Question 28

What are structural differences in male and female brains?

Answer 28

Male brains are ~10% larger; female brains have a thicker cortex and more grey matter.

Question 29

What are some functional differences in behaviour between boys and girls?

Answer 29

Different toy preferences, with boys showing a preference for cars and girls for dolls.

Question 30

What influences sexual orientation?

Answer 30

Biological correlates such as brain differences in SCN, INAH-3, and anterior commissure.

Question 31

What is the role of testosterone in sexual orientation?

Answer 31

It influences brain differentiation during critical periods of development.

Question 32

What is the 2D:4D finger ratio?

Answer 32

The ratio of the height of the 2nd finger to the 4th finger, associated with prenatal testosterone exposure.

Question 33

What cognitive performance differences exist between androphilic and gynophilic men?

Answer 33

Androphilic men show better verbal abilities than gynophilic men, while gynophilic men show better visuospatial abilities than androphilic men.

Question 34

How do gynophilic and androphilic women compare in mental rotation tasks?

Answer 34

Gynophilic women are faster at mental rotation tasks than androphilic women.

Question 35

What does the 2D:4D finger ratio indicate?

Answer 35

Lower ratios (shorter index finger relative to ring finger) are associated with higher prenatal testosterone.

Question 36

What is the 2D:4D ratio trend among butch lesbians?

Answer 36

Butch lesbians tend to have more masculine 2D:4D ratios.

Question 37

Are there consistent 2D:4D findings in androphilic men?

Answer 37

No consistent 2D:4D findings in androphilic men.

Question 38

What are oto-acoustic emissions (OAEs)?

Answer 38

When ears are stimulated with a click, they emit a sound back.

Question 39

How do women's OAEs compare to men's?

Answer 39

Women’s OAEs are louder and more frequent than men’s.

Question 40

What effect does prenatal testosterone exposure have on OAEs?

Answer 40

Prenatal testosterone exposure reduces OAEs.

Question 41

How do gynophilic women's OAEs compare to gynophilic men’s?

Answer 41

Gynophilic women’s OAEs are closer to gynophilic men’s than to androphilic women’s.

Question 42

What is the likelihood of CAH females being gynophilic?

Answer 42

CAH females are more likely to be gynophilic than non-CAH females.

Question 43

What do twin studies suggest about genetic contributions to sexual orientation?

Answer 43

Higher concordance for sexual orientation in monozygotic twins than dizygotic twins.

Question 44

What is the range of concordance estimates for sexual orientation?

Answer 44

Concordance estimates range from 30-100%.

Question 45

Is heritability for sexual orientation possibly higher in men or women?

Answer 45

Possibly higher heritability for women than men.

Question 46

What genetic link is suggested for androphilic men?

Answer 46

Androphilic men often have androphilic maternal uncles, suggesting an X-chromosome link.

Question 47

What are potential explanations for the maintenance of non-reproductive orientations?

Answer 47

Heterozygote advantage, different genetic effects in males vs. females, and kin selection.

Question 48

What is the Fraternal Birth Order Effect?

Answer 48

The more older brothers a male has, the higher the likelihood of being androphilic.

Question 49

What is the maternal immune hypothesis?

Answer 49

Mother’s immune system reacts to Y-linked proteins, influencing brain development.

Question 50

What influences sexual orientation?

Answer 50

Sexual orientation is influenced by biological developmental factors, hormonal, genetic, and environmental factors.

Question 51

What brain differences are observed in MtF and FtM individuals?

Answer 51

MtF individuals show feminine cortical thickness, while FtM individuals show masculine basal ganglia.

Question 52

What do twin studies indicate about gender dysphoria?

Answer 52

Higher concordance in monozygotic twins for gender dysphoria and sexual orientation.

Question 53

What is the impact of environmental and cultural influences on sexual orientation?

Answer 53

Minimal effects on sexual orientation; social influences impact behavior, not orientation.

Question 54

What are the conclusions about sexual differentiation and orientation?

Answer 54

Biological, hormonal, and genetic factors drive sexual differentiation and orientation.