Chapter 2: Biological Changes

Question 1

Definition of Puberty [3]

Answer 1

• Pubertas = adult; pubescere = to grow hairy
• Period when sexual reproduction starts
• Changes driven by the endocrine system

Question 2

Puberty - [2] Key points

Answer 2

• No new hormones are created, just changes in existing systems
• Adrenal glands develop around age 6 and produce DHEA (promotes hair growth, metabolism, and stress control)

Question 3

[3] key changes in puberty

Answer 3

1. Rapid Growth: Noticeable changes in height and weight.
2. Primary Sex Characteristics: Hormonal changes leading to sexual organs’ development.
3. Secondary Sex Characteristics: Physical changes not directly related to reproduction (e.g., breast development, body hair).

Question 4

[3] components of the endocrine system (ES)

Answer 4

• Glands (e.g., hypothalamus, pituitary)
• Hormones (e.g., GnRH)
• Organs and substances that influence development

Question 5

Hypothalamus [4]

Answer 5

• Bean-sized gland under the brain cortex
• Initiates hormonal changes by activating GnRH neurons
• Regulates thirst, hunger, and sexuality
• Damage can lead to mood disorders, obesity, thyroid problems

Question 6

Pituitary Gland [3]

Answer 6

• Pea-sized gland below the hypothalamus
• Known as the “master gland” because it controls hormone circulation
• Influences growth and sexual development through hormones like ACTH, LH, FSH, estradiol, and testosterone

Question 7

[3] Sex Hormones

Answer 7

• Estradiol: More in females (8x) than in males (2x)
• Testosterone: Much higher in males (20x) compared to females (4x)
• Causes bodily changes and development of secondary sex characteristics

Question 8

Hormonal Feedback Loop [2]

Answer 8

• Hypothalamus activated by GnRH neurons every 2 hours
• Increased body fat signals puberty onset through hormones like leptin

Question 9

What is the role leptin plays in the onset of puberty? [1]

Answer 9

High levels of leptin inhibit kisspeptin, thus delaying puberty

Question 10

The earliest phase of puberty, which begins before any other phase? [1]

Answer 10

Adrenarche which begins at about 6 yrs old

Question 11

Somatic Development [3]

Answer 11

• Growth Spurt: Rapid increase in height & weight
• Peak Height Velocity: Fastest growth point
• Epiphysis: Closing of bone ends when growth is complete

Question 12

Sexual maturation - Girls Sequence [6]

Answer 12

1. 7 to 13: growth of breasts
2. 7 to 14: growth of pubic hair
3. 9 1/2 to 14 1/2: body growth
4. 10 to 16 1/2: menarche
5. About two years after pubic hair: underarm hair
6. About the same time as underarm hair: oil-and sweat producting glands

Question 13

Sexual maturation - Boys sequence [7]

Answer 13

1. 10 to 13 1/2: growth of testes
2. 10 to 15: growth of pubic hair
3. 10 1/2 to 16: body growth
4. 11 to 14 1/2: growth of penis
5. About two years after pubic hair: facial and underarm hair
6. About the same time as underarm hair: oil-and sweat producting glands, acne

Question 14

Sexual maturation - Primary Sex Characteristics [2]

Answer 14

• Males: Growth of penis and testes; spermarche (around 12 years)
• Females: Growth of ovaries, uterus, and vagina; menarche (first menstruation)

Question 15

Sexual maturation - Secondary Sex Characteristics [2]

Answer 15

• Males: Hair growth, sweat glands, rougher skin
• Females: All the above plus breast enlargement

Question 16

Testosterone & Aggression - Activational Effects [1]

Answer 16

Hormones activate behaviors linked to aggression

** higher sensitivity to environment → more irritability
e.g., changes in BMR → faster reaction times or more energy vs lethargy

Question 17

Testosterone & Aggression - Genotype x Environment Interactions [2]

Answer 17

• Inherited traits evoke responses from others
• Hormones + individual sensitivity + context influence behavior

Question 18

Testosterone & Aggression - Key findings [2]

Answer 18

• Weak correlations between testosterone and aggression
• Effect size declines with age

Question 19

What are the [3] biological changes during puberty?

Answer 19

1. Physical Growth
2. Development of Primary Sex Characteristics
3. Development of Secondary Sex Characteristics

Question 20

What is the role of the endocrine system? [1]

Answer 20

consists of glands and hormones that regulate physical and sexual development during puberty

Question 21

Explain the hormone feedback loop [1]

Answer 21

• involves the hypothalamus, which activates GnRH neurons to signal the pituitary gland.
• This gland then releases hormones that influence growth and sexual maturation.
• Increased body fat and high levels of leptin trigger the onset of puberty by affecting the activation of the hypothalamus and hormone release.

Question 22

What are the key aspects of somatic development and sexual maturation? [2]

Answer 22

• Somatic development is about your body’s growth, like getting taller and heavier. (growth spurt)
• Sexual maturation means your body becomes capable of reproduction, which includes changes like starting your period (menarche) for girls and producing sperm (spermarche) for boys