EXAM 1: Chapter 2 - Biological Development Flashcards
What is sex
The distinction between genetic females (XX), genetic males (XY) and intersex individuals
- Also includes variations in associated hormonal concentrations and activity
What is gender
Social assignment or self-categorization as a man/boy, woman/girl, non-binary
What are gametes (germ cells)
Reproductive cells - egg and sperm - that contain only half the genetic material of all other cells in the body
- sex chromosomes are passed on through gametes
What is the role of sex chromosomes
Organizing and activating processes across development
Overt signs of variations beyond XX and XY dichotomy often emerge in __________
Puberty
What occurs during the prenatal development phase
Organizing occurs
Sex is determined by the presence or absence of androgens, allowing for the formation, if present, of male external organs
- androgen insensitivity
- congenital adrenal hyperplasia (hypersensitivity)
What occurs during the adolescence period
Activating
Puberty
What is puberty
The time between the first onrush of hormones and full adult physical development
How long does puberty generally last
About 4 years
But variations (1-7 years)
Many more years are required to achieve psychosocial maturity
What is the endocrine system
Collection of glands that produce hormones that regulate bodily functions
What does the gland the ovaries produce (hormone), what is the target organ and what is the function
Estrogen / progesterone
Uterus
Menstrual cycle
What does the gland the testes produce (hormone), target organ and function
Testosterone
Many organs
Male characteristics
What is the hormone DHEA (Dehydroepiandrosterone)
Precursor to androgens and estrogens that increase during puberty, peak around 25 years and then declines steadily across aging
What is the hormone GnRH (Gonadotropin-releasing hormone)
Released by hypothalamus and triggers other hormones in the pituitary gland
What is the follicle-stimulating hormone (FSH)
Stimulates gonads to produce gametes
What is the luteinizing hormone (LH)
Triggers ovulation, modulates ovaries hormone production and menstrual cycle
Causes testes to produce testosterone and modulates testes growth
What is estrogens
Hormone responsible for female sex characteristics
(Males also have this just lower levels)
What is testosterone
A type of androgen responsible for male sex characteristics
(Females also have this but in much lower levels)
What is the HPG (hypothalamus-pituitary-gonad) axis
Controls gonads and stress hormones through feedback loops
What are gonads
The paired sex glands (ovaries in females, testicles in males)
Produce sex hormones and gametes
Use of feedback loops
What is gonadarche
The onset of gonad maturation
What is andrenarche
Hormonal changes prior to puberty (6-8 years old)
Activation of adrenal glands to stimulate body growth
- begins sensitive period of HPA axis responses (stress sensitivity!)
Adolescent growth spurt
Rapid gain in height and weight (~10 yrs for females, ~12 for males)
Gain fat and muscle, bone density lung/heart size
Lasts ~2 years
What is menarche
A girl’s first menstrual period, signaling that she has begun ovulation
- pregnancy is biologically possible, but ovulation and menstruation are often irregular for years after menarche
What is spermarche
A boys first ejaculation of sperm
- erections can occur as early as infancy, but ejaculation signals sperm production
- often occurs as nocturnal emissions (“wet dreams”)
What are Primary sex characteristics
The parts of the body that are directly involved in reproduction, including the vagina, uterus, ovaries, testicles, and penis
What are secondary sex characteristics
Physical traits that are not directly involved in reproduction but that indicate sexual maturity, such as voice changes, facial/body hair, acne, breast development
What are ways to measure pubertal onset
Salivary hormone levels
Self- and parent-report of secondary sex characteristics
What occurs to sleep patterns during puberty
Delayed phase preference
Puberty drives increases in melatonin (and sleep) about 2 hours later than pre-pubertal children
What is melatonin
The hormone that influences sleep onset and maintenance
What is natural adolescent sleep schedule
1 am to 10 am
How many hours of sleep per night do adolescents need
9 hours per night
Poor sleep can lead to irritability, cognitive interference and risky behavior
At what age is early-onset puberty
< age 8 in girls and < age 9 in boys
What can occur during early-onset puberty
Adolescents who look older are treated differently by peers and adults
Mismatch with cognitive and emotional maturity -> stress!
Greater rates of risky behavior (ex. Smoking)
Greater popularity, also athleticism and confidence (more so in boys)
There are greater psychosocial downsides for boys or girls during early onset puberty
Girls
Lower self-esteem, more depression, anxiety and poorer body image than later-maturing female peers
Greater risk of dating violence, sexual harassment, relational aggression
What is late-onset puberty
> age 13 in girls and >age 14 in boys
Protective affect for girls
- less depression, less appearance related anxiety, less relational aggression experiences
Greater psychosocial downsides for boys
- poor body image/dissatisfaction, more depression, anxiety, effects may wane following maturation
- mixed research
What is some peer context to late onset puberty
Later-maturing boys may only experience increased anxiety/depression if they have poor peer relaitionships
What is racial ethic identity and school context of late onset puberty
Early-maturing black adolescents have more experiences with racial discrimination
Greater depression, depending on context
- interaction with degree of perceived positive public regard among black adolescents
What factors drive individual differences in HPG axis initiation of puberty ?
Genetics
Nutrition and Health
Stress
How do genetics play a role in pubertal timing
Pubertal timing is polygenic
- adolescents experience similar timing as parents
- identical twins are more similar in timing than fraternal twins
How does nutrition and health impact pubertal timing
Leptin - protein found in fat
- signals HPG axis to increase hormone secretion
Body Mass Index (BMI) predicts pubertal timing
How does stress impact pubertal timing
Can trigger hormone fluctuations at any age
Early and severe life stress associated with early-onset puberty
Low SES families experience more stress and tend to have earlier timing
- couples with ethnicity due to systemic economic inequality in US
Family dynamics and even family structure appear to play a role
What is a secular trend ?
The change from one generation to the next in an aspect of development (ex. Height, shoe size, pubertal timing)
What are some mental health factors of pubertal timing
It has bidirectional effects with mental health
Mental health difficulties commonly energy during puberty
- anxiety
- depression
- suicidal thoughts and behaviors
- eating disorders
Suicidal thoughts and behaviors during puberty
Suicidal thoughts and behaviors
- death by suicide is 2nd leading cause of death among 15-24 year olds
- ~20% of high school students report suicidal thought
- ~9% report suicide attempt
Interactions with early adversity and pubertal timing
How are eating disorders related to pubertal timing
In order from least to most prevalent
Anorexia nervousa
- restricted food intake leading to low BMI
Bulimia nervosa
- binge eating with purging (low BMI not necessary)
Binge eating disorder
- binge eating without purging
Accompanied by disruptions with puberty due to malnutrition, medical complications, hormonal fluctuations due to weight fluctuations
Health in adolescence and emerging adulthood
Intervention and prevention efforts focus on supporting
- healthy nutrition
- physical activity
- access to care
- health literacy - knowledge skills and attitudes about health and the ability to obtain, process, and understand health information, and healthy decisions
