physical changes

Endocrine System

- Made up of the hypothalamus, pituitary gland, thyroid gland, adrenal glands, & gonads
- Involved with controlling the hormones involved in puberty

Endocrine System - Hypothalamus

- Triggers the endocrine system
- Signals hormonal changes
- Gonadotropin-releasing hormone (GnRH) production increases with body fat
- Fat cells produce leptin that provides signal to release GnRH

Endocrine System - Pituitary Gland

Releases gonadotropins (follicle-stimulating & luteinizing hormones)

Endocrine System - Thyroid Functioning

Poor functioning in adolescence related to abnormalities in sexual development

Endocrine System Feedback Loop

Gonads release sex hormones --> adrenocorticotropic hormone (ACTH) causes adrenal glands to increase androgen production --> hormone levels detected & controlled by hypothalamus

Hormones & Sex Differences

- Estrogens & androgens exist in both sexes
- More sex-specific hormones are released as puberty progresses
- Estrogen is more powerful
- We have way more testosterone in our bodies

Growth Spurts

- Girls typically start growth spurts earlier (11) than boys (15)
- Could be linked to body image & social comparison as girls notice the changes in their bodies earlier than boys

Muscle Mass & Body Fat

- Muscle growth is similar until about 14
- Body fat growth starts much earlier for women (age 2) as it's required for childbirth
- Men don't require energy storage in the same way women do

Body Mass Index (BMI)

- Ratio of weight to height
- Definitions are cultural & arbitrary
- Not a meaningful number

Issues with BMI

- Not a direct measure of body fat
- Doesn't indicate body fat distribution
- Doesn't account for muscle mass
- Doesn't distinguish between men/women or different ethnicities

Obesity

- Chronic, progressive, & relapsing disease
- The presence of abnormal or excess adiposity that impairs health & social wellbeing
- Medical professionals should identify the causes & consequences of abnormal/excess cell adiposity on the patient's physical, mental, & functional health

Obesity Treatment Focus

- Establishing values & goals of treatment
- Foster self-efficacy
- Provide non-judgmental & stigma-free clinical practice

Adolescents & Weight

- Prevalence of obesity is about 7%
- Weight among youth is increasing in developing countries too
- Doctors focus on health risks (breathing, fractures, hypertension, insulin resistance) when preaching weight loss

Diet & Exercise

- 36% of adolescents in the US eat fast food daily
- African American & Latino adolescents are more likely to consume fast food & drinks (consider socioeconomic status)
- 15-year-olds spend little time (less than 1hr on weekdays, less than 30mins on weekends) engaging in physical activity
- Time spent on screens = time not spent outdoors

Genes & Environment in Obesity

- There's little conversation around the intersection of diet, physical activity, & neuroendocrine factors
- There are hereditary & family concordance in obesity
- Different genes control protein synthesis & function involved in appetite, energy expenditure, metabolism, & adipogenesis

Attard, Herring, Howard, & Gordon-Larsen (2013) - Puberty & Obesity

- A longitudinal study that followed participants from adolescence into adulthood
- Looked at rates of diabetes, hypertension, & inflammation throughout the lives of the participants

Attard, Herring, Howard, & Gordon-Larsen (2013) - Puberty & Obesity Findings

- Overall prevalence of diabetes was 5.5%
- Overall prevalence of hypertension was 26.4%
- Overall prevalence of inflammation was 31.3%
- Odds of diabetes doubled if you increase 8 BMI points during 15-20 at the age of 20
- Odds also doubled if BMI was 20 across the entire study period

Attard, Herring, Howard, & Gordon-Larsen (2013) - Puberty & Obesity Implications

It's possible that environmental factors have the most impact during growth than after growth

Critical Messagin for Adolescent Health

- The process is more important than the outcome
- Emphasize healthy habits for eating, sleeping, physical exercise, & stress management

Primary Sex Characteristics

Egg and Sperm Production

Bodily changes ti support reproduction (enlargement of penis & testes, vaginal organ, uterus, ovaries)

Menarche

First menstrual period (mature egg released 28 days; 400 ova over lifetime, first 4 years of ovulation is unpredicted)

Spermarche

First production of sperm around ages 12-14 (100-500 million sperm per ejaculation)

Sperm recognized by womans vody as a foreign and thus attacked by immune system

Secondary Sex Characteristics

• Not directly related to reproduction but is triggered by puberty

• More hair including pubic hair

• Sweat glands increase production 

• Deepening of voice

• Enlargement of breasts (needed for milk production post-partum)