Lecture 2 Puberty & Physical Development

What is puberty?

A synchronized biological event that gradually transforms a child into an adult.

What role do hormones play in puberty?

Hormones are chemical messengers produced by glands that regulate growth and bodily functions.

Which gland controls the endocrine system?

The hypothalamus gland.

What is the function of the pituitary gland during puberty?

It sends hormones to other endocrine glands to regulate their activity.

What hormones do the thyroid gland release?

Hormones that impact metabolism, heart rate, digestion, temperature, brain development, and fertility.

What hormones do the adrenal glands produce?

Cortisol, aldosterone, and adrenaline, which help regulate metabolism, blood pressure, and stress response.

What are gonads and their role in puberty?

Gonads are the ovaries in females and testes in males, producing sex hormones like estrogens and androgens.

What is the HPG Axis?

A feedback loop involving the hypothalamus, pituitary gland, and gonads that regulates sex hormone levels.

What triggers the HPG Axis to start functioning?

The hypothalamus begins producing more GnRH when it becomes less sensitive to sex hormones.

What is andrenarche?

The beginning of adrenal involvement in puberty, marked by increased production of DHEA.

What is the significance of DHEA in puberty?

It leads to the first appearance of pubic hair and is linked to brain changes and sexual attraction.

What is the average age for the start of the adolescent growth spurt in girls?

Around age 10.

What is the average age for the end of the adolescent growth spurt in boys?

Around age 18.

What is Peak Height Velocity?

The fastest change in height during the growth spurt, typically around age 12 for girls and 14 for boys.

Why do boys generally end up taller than girls?

Boys experience a growth spurt two years later than girls, allowing them to grow more during adolescence.

What percentage of adult body weight is gained during adolescence?

About half of adult body weight.

What is asynchronicity in physical development?

The phenomenon where different body parts develop at different rates during adolescence.

By age 15, how much more muscle mass do boys have compared to girls?

About 20% more muscle mass.

What is the relationship between testosterone and muscle development in boys?

Higher testosterone levels in boys are closely linked to increased muscle mass.

What factors are believed to influence the onset of puberty?

Body weight, body fat percentage, insulin-like growth factor, kisspeptin, and leptin levels.

What is menarche?

The first menstrual period, typically occurring when a girl reaches a critical body weight.

How do sex hormones change during puberty in boys and girls?

Testosterone rises significantly in boys, while estradiol levels increase more in girls.

What is the role of kisspeptin in puberty?

Kisspeptin may influence the secretion of GnRH, affecting the onset of puberty.

How does the hypothalamus respond to rising levels of sex hormones?

It reduces the production of GnRH, signaling the pituitary to decrease LH and FSH production.

What is the significance of leptin during puberty?

Leptin levels increase during puberty and are necessary for the creation of kisspeptin.

What hormone is closely linked to muscle production in boys during adolescence?

Testosterone

What is the typical muscle-to-fat ratio for girls by the end of puberty?

About 5:4, with slightly more muscle than fat.

How does the muscle-to-fat ratio differ for boys at the end of puberty?

Boys typically have about three times as much muscle as fat.

What physical changes do boys typically experience during puberty?

Boys gain more width in the shoulders than hips.

What physical changes do girls typically experience during puberty?

Girls gain more width in the hips than shoulders.

What societal ideals can lead to dissatisfaction with body image among adolescent girls?

The North American ideal of feminine beauty, which includes long legs, slender bodies, and narrow hips.

What are some potential consequences of body dissatisfaction in adolescent girls?

Preoccupation with controlling or losing weight, and potential development of eating disorders like bulimia or anorexia.

What happens to the size of the heart and lungs during puberty?

Both increase in size, with a greater increase in boys.

What triggers the onset of puberty in girls?

Increased levels of LH (luteinizing hormone) and FSH (follicle-stimulating hormone).

At what average age does menarche occur in Canada?

Approximately 13 years.

What is the secular trend regarding menarche?

The tendency for puberty to start at younger ages over time.

What factors can influence the timing of menarche?

Nutrition, body mass index, health, and environmental factors.

What is the first sign of puberty in girls?

Breast bud development.

What is the first sign of puberty in boys?

Growth of the testes and scrotum.

What changes occur in boys' voices during puberty?

Voices get lower in pitch and more resonant due to longer vocal cords and an expanded larynx.

What is the significance of Tanner Stages in puberty?

They are used to estimate pubertal maturity.

What emotional impacts can puberty have on girls?

It can lead to internal stress, ambivalence, and conflict as they transition from childhood.

How can early maturation affect girls socially?

Early-maturing girls may draw attention from older boys, leading to potential social risks.

What role does sebum play during puberty?

It can lead to blackheads and acne due to increased skin gland activity.

What is the relationship between family dynamics and the timing of puberty?

Family conflict and stress can influence stress hormones, affecting maturation timing.

What is a common worry for girls regarding breast development?

Changes in relationships with male peers.

What can help girls have a more positive attitude towards menstruation?

Positive preparation for menarche.

What is the impact of malnutrition on menarche?

Malnutrition and conditions like anorexia can delay the onset of menarche.

What is the effect of intensive physical training on puberty timing in girls?

It tends to delay puberty due to lower body fat and higher exertion levels.

What are some psychological effects of early maturation in girls?

Early-maturing girls may experience increased anxiety, depression, and complicated peer relations.

What is semenarche?

Semenarche is the first emission of seminal fluid in boys.

How do early-maturing boys typically fare socially?

Early-maturing boys are often more popular with peers and may have athletic advantages, but they can also show increased hostility, depression, and delinquency.

What is the Deviance Hypothesis regarding puberty timing?

The Deviance Hypothesis suggests that being noticeably different from peers in puberty is stressful, making it preferable to be 'on time' rather than 'off time.'

What does the Stage Termination Hypothesis propose?

The Stage Termination Hypothesis posits that early puberty can disrupt the completion of earlier developmental tasks, affecting adolescents' ability to cope with changes.

What is the Adult Resemblance Hypothesis?

The Adult Resemblance Hypothesis states that individuals who appear more adult-like are treated more like adults, which can have both positive and negative effects.

How do parents typically respond to their child's puberty?

Parents may adapt to adolescent changes by either becoming more supportive or experiencing increased conflict as teens seek independence.

What are puberty rites and their common features?

Puberty rites mark the transition to adulthood and often include separation, transition, and incorporation into adult roles.

What is synaptic pruning?

Synaptic pruning is the process of eliminating less-used brain circuits, which occurs significantly during puberty and adolescence.

What role do neurotransmitters play in brain development?

Neurotransmitters, such as acetylcholine, dopamine, and serotonin, are chemicals that transmit signals across synapses between neurons.

What changes occur in the brain during adolescence?

During adolescence, the brain reaches nearly adult size, experiences synaptic pruning, and sees increased efficiency in decision-making areas.

How does myelination affect adolescent brain function?

Myelination increases the speed and efficiency of nerve signal transmission, particularly in the prefrontal cortex, which continues to develop into the twenties.

What emotional changes are common in early adolescents?

Early adolescents often experience greater emotionality due to rapid hormonal changes and various life transitions.

How do physical changes during puberty affect body image in adolescents?

Adolescents, especially girls, often criticize their appearance, with girls perceiving themselves as overweight even when they are not.

What health issues are prevalent among North American teens?

Many North American teens are sleep-deprived, have unhealthy eating habits, and experience a rise in obesity rates.

What is the delayed phase preference in adolescents?

The delayed phase preference refers to a shift in melatonin levels during puberty that affects sleep patterns, leading to later sleep times.

What is the impact of media on body image for boys and girls?

Boys often get closer to cultural ideals of muscularity, while girls may feel pressured to lose weight, moving further from ideal beauty standards.

What is the relationship between puberty and mood?

Puberty can lead to mood swings and emotional instability due to hormonal changes and increased life stressors.

What is the significance of the cerebral cortex in brain development?

The cerebral cortex is responsible for complex processes such as thinking, memory, and judgment, and undergoes significant development during adolescence.

What is the role of the limbic system in adolescent behavior?

The limbic system, which develops more quickly than impulse control systems, is linked to heightened emotional responses and risk-taking behavior in adolescents.

How does peer pressure influence adolescent behavior?

Adolescents may engage in riskier behaviors due to peer pressure, particularly when they are more popular or appear older.

What are some common cultural puberty rites for girls?

Common rites include celebrations like 'Sweet sixteen' and quinceañeras, often marking the onset of menstruation.

What are some common cultural puberty rites for boys?

Traditional rites for boys may involve harsher experiences, preparing them for adult roles such as hunting or warfare.