Chapter 2: Biological Changes Flashcards
Definition of Puberty [3]
- Pubertas = adult; pubescere = to grow hairy
- Period when sexual reproduction starts
- Changes driven by the endocrine system
Puberty - [2] Key points
- 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)
[3] key changes in puberty
- Rapid Growth: Noticeable changes in height and weight.
- Primary Sex Characteristics: Hormonal changes leading to sexual organs’ development.
- Secondary Sex Characteristics: Physical changes not directly related to reproduction (e.g., breast development, body hair).
[3] components of the endocrine system (ES)
- Glands (e.g., hypothalamus, pituitary)
- Hormones (e.g., GnRH)
- Organs and substances that influence development
Hypothalamus [4]
- 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
Pituitary Gland [3]
- 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
[3] Sex Hormones
- 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
Hormonal Feedback Loop [2]
- Hypothalamus activated by GnRH neurons every 2 hours
- Increased body fat signals puberty onset through hormones like leptin
What is the role leptin plays in the onset of puberty? [1]
High levels of leptin inhibit kisspeptin, thus delaying puberty
The earliest phase of puberty, which begins before any other phase? [1]
Adrenarche which begins at about 6 yrs old
Somatic Development [3]
- Growth Spurt: Rapid increase in height & weight
- Peak Height Velocity: Fastest growth point
- Epiphysis: Closing of bone ends when growth is complete
Sexual maturation - Girls Sequence [6]
- 7 to 13: growth of breasts
- 7 to 14: growth of pubic hair
- 9 1/2 to 14 1/2: body growth
- 10 to 16 1/2: menarche
- About two years after pubic hair: underarm hair
- About the same time as underarm hair: oil-and sweat producting glands
Sexual maturation - Boys sequence [7]
- 10 to 13 1/2: growth of testes
- 10 to 15: growth of pubic hair
- 10 1/2 to 16: body growth
- 11 to 14 1/2: growth of penis
- About two years after pubic hair: facial and underarm hair
- About the same time as underarm hair: oil-and sweat producting glands, acne
Sexual maturation - Primary Sex Characteristics [2]
- Males: Growth of penis and testes; spermarche (around 12 years)
- Females: Growth of ovaries, uterus, and vagina; menarche (first menstruation)
Sexual maturation - Secondary Sex Characteristics [2]
- Males: Hair growth, sweat glands, rougher skin
- Females: All the above plus breast enlargement
Testosterone & Aggression - Activational Effects [1]
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
Testosterone & Aggression - Genotype x Environment Interactions [2]
- Inherited traits evoke responses from others
- Hormones + individual sensitivity + context influence behavior
Testosterone & Aggression - Key findings [2]
- Weak correlations between testosterone and aggression
- Effect size declines with age
What are the [3] biological changes during puberty?
- Physical Growth
- Development of Primary Sex Characteristics
- Development of Secondary Sex Characteristics
What is the role of the endocrine system? [1]
consists of glands and hormones that regulate physical and sexual development during puberty
Explain the hormone feedback loop [1]
- 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.
What are the key aspects of somatic development and sexual maturation? [2]
- 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
