Ch. 1 - Biological Flashcards
What are some words that can be used to describe the physical growth process throughout adolescence?
regular/predictable
continuous
decelerating
When does the adolescent growth spurt typically occur? What causes this spurt?
11 in girls and 13 in boys
due to spontaneous release of growth and thyroid hormones as well as androgens
What are growth asynchronies?
head/hands/feet grow first, then arms/legs, then torso/shoulders
no smooth elongation of the body
rapid increase in limb length leaves teenagers awkward and out of proportion
How does fat and muscle distribution change over adolescence?
increase in both fat and muscle
muscle development more rapid for boys than girls
fat increases more rapidly (and in a greater amount for girls)
- much reach a certain amount to initiate menarche and continue menstruation
What is the difference between primary and secondary sex characteristic changes?
primary = reproductive organs (ex. testes, ovaries)
secondary = physical features
What area of the brain stimulates endocrine glands? What do these endocrine glands do?
hypothalamus stimulates endocrine glands
glands produce hormones
What hormones do the female and male sex glands produce?
male gonads -> androgens
female ovaries -> estrogen
What are the 6 main signs of pubescence in males?
- enlargement of testes and scrotum
- pubic hair
- penis begins lengthen, pubic hair becomes darker and coarser, growth spurt in height
- voice change
- axillary hair growth (armpits, face)
- some experience temporary breast enlargement
What order does facial hair grow in?
corners of upper lip sideburns chin cheeks neck
What are the 5 main signs of pubescence in females?
- development of breasts
- pubic hair
- body growth
- menarche
- underarm hair
What changes to the skin occur in both boys and girls?
rougher skin
sweat-producing glands
oily skin
acne
When has sexual maturity been reached?
girls - menarche
boys - first ejaculation
What are some factors that influence the timing and age of menarche?
nutrition and general health
- well-nourished = earlier period
geographical location
- warmer = later period
season
- most occur in summer, fewer in spring
family environment
- less cohesive homes = earlier period (relates to activation of hormones)
genetics
- mothers who mature early have daughters who mature early
What are some psychological implications of variations in development?
asynchrony often concerns adolescents
- worry about getting teased/judged
- feel abnormal
could be treated as older or younger than they actually are - perceptions of maturity are often judged in terms of physical appearance
What are some experiences shared by early maturing boys?
fewer psychological problems than late-maturers
more popular, looked up to
- social advantage in the short run
look mature so treated as older
advanced physical abilities -> acceptance/admiration -> positive self concept
What are some experiences shared by late maturing boys?
less popular
feel less skilled/competent
but later in life have the advantage
- become more curious, show social initiative
- had more time to develop coping skills and prepare for puberty
- success and satisfaction become more dependent on intellectual skills later in life
What are some experiences shared by early maturing girls?
society values slenderness
- causes negative reactions/comparisons to their own larger size/weight
popular with boys/earlier sexual activity
emotional issues
- lower self-image/self-esteem
- higher rates of depression/anxiety, eating disorders, and problem behaviour
What is pseudo-independence?
early maturing young people seem older and are given adult-like privileges and expectations before they are truly ready
How does maturation timing and supervision relate to alcohol abuse?
in early maturing girls, low supervision leads to large increase in alcohol abuse between grades 7-10 compared to high supervision
no difference in late maturing girls
What is body image?
concept/perception of what our body looks like
influenced by other people’s real or imagined reactions to use
What is body attitude?
how we feel about our body’s form/appearance
What does the prefrontal cortex do?
aka control centre or CEO
self-control, judgement, emotional regulation, organization, planning
What brain changes occur during adolescence?
growth spurt just before puberty
- new brain cells and neural connections
- “cells that fire together, wire together”
- different regions undergo growth spurts at different times
increased myelinization
- forming insulation around neurons to make information travelling smoother and more efficient
growth followed by pruning
- extra branches get pruned back to improve organization
- happens back to front
What are the effects of pruning occurring back to front?
prefrontal cortex that underwent growth first is pruned last
frontal lobes actually shrink during adolescence - during this time it is not working as well as it could
What areas of the brain undergo growth spurts first?
areas involved in more basic functions mature first
What is the role of the nucleus accumbens?
seeks pleasure and reward
developed early on in adolescence (makes sense)
What is the “adolescent dilemma” of brain development?
sensation seeking areas turned on while brain areas that mediate these thoughts are not fully developed
reasoning and judgement areas of the frontal lobes continue to develop throughout all of adolescence
back to front development: why adolescents seem to lack good decision making, logical thinking/planning
What do the back areas of the brain control?
sensory, movement, coordination
develops first
What do the middle areas of the brain control?
aka limbic system
controls emotions
develops second
- becomes fully developed within adolescence, they can and often do respond to emotional content
What do the front areas of the brain control?
planning, reasoning, organization
executive functions
among the last to fully mature, not until 25 or later
How do adults and adolescents differ in interpreting emotions?
adults use prefrontal cortex and think logically
teens use amygdala - does deal with emotions but lacks some of the logic of the frontal lobe
- lead with their emotions, heightened emotional sensitivity
- automatic “hot” or “cool” responses
- can misread tone, expression
Where is most of the mental energy in decision making located in teenagers?
at the back
vs. the front in adults
makes sense as we know synaptic pruning begins at the back
When does grey matter volume peak? What is its role?
11 for girls, 13 for boys
then gradually declines
- indicates synaptic pruning (positive thing)
thin folding outer layer, where processes of thought/memory are
How can adolescence provide the chance to “create the brain you want”?
what you use gets stronger
consolidate circuits that are used, eliminate those that are not
current actions impact future brain
What is delayed phase preference?
adolescents prefer delayed phase of sleeping - later sleep and wake times than in childhood
melatonin increase times get later during puberty - 2 hours later by the end
but often not possible (ex. school start times)
How do melatonin and kisspeptin interact?
kisspeptin triggers puberty
melatonin
- triggered by dark, makes you sleepy
- levels fluctuate throughout the day
- suppresses kisspeptin, contributes to puberty delay
How does increased vs. decreased light exposure affect puberty?
increase in light -> decrease melatonin -> decrease in kisspeptin suppression -> earlier puberty
decrease in light -> increase melatonin -> increase in kisspeptin suppression -> later puberty
What other factors suppress melatonin? What are the effects of suppressed melatonin?
lights
electronics
make us less sleep and make it easier to stay up later
What is sleep debt?
the difference between the amount of sleep your body needs and the amount you actually get
if you are short on sleep, your total sleep deficit builds, resulting in long-term sleep debt
-long-term sleep debt can’t be fully recovered
What is sleep deprivation?
accumulation of sleep debt
adolescents often chronically sleep deprived, commonly viewed as an epidemic
What are some impacts of sleep deprivation?
daytime sleepiness inability to concentrate poor grades/underachievement reduced cognitive function and learning capacity poor impulse control weight gain drowsy driving incidents exacerbate ADHD/ASD symptoms affect mood/emotional regulation shapes brain - decrease in grey matter
How does sleep deprivation lead to reduced cognitive function and learning capacity?
REM sleep consolidates learning and memories
opportunity is reduced when you don’t get enough sleep
How does sleep deprivation lead to weight gain?
slower metabolism
hormonal tendency to eat more
How can drowsy driving be especially dangerous in adolescence?
can be amplified by lack of driving experience and distracted driving
similar to effects of alcohol consumption
How may COVID be affecting adolescent sleep?
decreased natural light
decreased physical activity
increased screen time
light based-cues we use for wakefulness and sleep may be reduced
What are the 3 chief physical manifestations of puberty?
rapid growth acceleration -> increased height and weight
development of primary sex characteristics (sex glands)
- results in hormonal changes
development of secondary sex characteristics (breasts, genitals body hair)
What are hormones?
specialized substances that are secreted by an endocrine gland and enter the bloodstream to travel throughout the body
many hormones at work during puberty carry instructions by activating GnRH neurons
What is the role of the endocrine system?
produces, circulates, and regulates levels of hormones
What are glands?
organs that stimulate particular parts of the body to respond in specific ways
What is the Hormonal Feedback Loop?
receives instructions to increase or decrease circulating levels of particular hormones from CNS
- mainly from firing of GnRH neurons
attempts to maintain set point
created by HPG axis
What is a set point?
physiological level of a hormone that the body attempts to maintain
monitored by hypothalamus
What is the HPG-axis?
hypothalamic-pituitary-gonadal axis
hypothalamus monitors levels and signals/inhibits pituitary gland
pituitary gland signals the gonads to release more hormones
neurophysiological pathway that creates feedback loop
What is adrenarche?
maturation of the adrenal glands
- brain system that controls how we responds to stress
- why adolescence is a period of vulnerability for many serious mental disorders
- excessive release of cortisol (stress hormone) which can kill brain cells and is also associated with physical health problems
stimulates feelings of sexual attraction and development of body odour
What triggers puberty?
HPG axis is reawakened to signal body that it is time for puberty
- partially due to “puberty alarm” set by genetics, some due to signals that tell the brain it is time to prepare for child-bearing
stimulated by increase in kisspeptin
- leptin stimulates, melatonin suppresses
- more fat cells and more light exposure = earlier puberty
Why does fat levels and light exposure affect puberty timing?
evolutionary history
once someone has developed enough fat and senses the season is right for gathering food, start preparing for child-birth
our genes don’t know we no longer live in resource-scarce world
Not all behaviour changes that appear at adolescence result from hormone changes at this time. Why is this?
presence of certain hormones early in life can result in behaviour changes that don’t emerge until adolescence
certain changes likely result from prenatal and pubertal hormones
What is epiphysis?
closing of the ends of long bones, terminating growth in height at the end of puberty
What is peak heigh velocity?
time when adolescent is growing most rapidly
4 inches per year for boys, 3.5 for girls - same rate as a toddler
What happens first: fertility, or adult-like appearance?
boys fertile before adult-like appearance
opposite for girls
When is the range of ages in which puberty can begin? What is the range of how long it may take to complete?
onset can occur as early as 5 in girls or 6 in boys and begin as late as 13
complete maturation can be as short as half a year or as long as 6 years for girls
- 2-5 years for boys
What determines timing and tempo of puberty?
largely inherited
environment plays a role in where the individual falls within the range set by genetics
What are the 2 biggest environmental influences on puberty timing/tempo?
nutrition and health
earlier among those who are better nourished
chronic illness, excessive exercise push puberty later
What are pheromones? What role do they play?
chemicals secreted by animals that stimulate certain behaviours in other members of the species
exposure to unrelated members of the other species may accelerate puberty
ex. menstrual period synchronization in female roommates
What is the secular trend?
tendency over the past 2 centuries for individuals to be larger in stature and to reach puberty earlier
due to improvements in health and nutrition
also due to increase in leptin due to increased obesity
also evidence that it takes longer to complete
What behavioural trend has resulted from age of puberty dropping?
amount of time between arousal of sensation seeking and maturation of self-control has grown
creating larger window of vulnerability to risky behaviour
- adolescent mortality has risen
What is the maturational deviance hypothesis?
those who stand far apart from their peers are more likely to experience psychological distress than those who blend in more easily
ex. early maturing girls more likely to be sexually harassed, early maturing teens more likely to participate in deviant activities
What is the developmental readiness hypothesis?
younger adolescents are less ready to cope with the challenge of puberty than the older ones
What is white matter?
cells other than neurons that also play a role in transmitting electrical impulses among brain circuits
produce myelin for myelination
What cells go through synaptic pruning?
grey matter
Why is adolescence called “the age of opportunity”?
second period of heightened brain plasticity
What is plasticity?
capacity of the brain to change in response to experience
sculpted by both passive exposure and active experience, allows us to acquire new information and abilities
What is the difference between developmental plasticity and adult plasticity?
developmental = extensive remodelling of brain circuitry in response to experiences while the brain is still maturing
adult = relatively minor changes in brain circuits as a result of experiences after the brain has matured
How can the malleability of the brain also be a risk?
brain more vulnerable to damage from physical or psychological harms
What are the 2 most important brain function changes involving the prefrontal cortex?
response inhibition
functional connectivity
What is functional connectivity?
more likely to use multiple parts of the brain simultaneously and coordinate activity between brain areas
What is the limbic system?
middle section of the brain
involved in processing emotions, social information, and rewards/punishment
What results from better connection between prefrontal cortex and limbic system?
improvements in ability to regulate emotions and coordinate thoughts and feelings
What is the role of dopamine and serotonin?
dopamine - experiencing reward
serotonin - experiencing different moods
changes in the way the brain is affected by these neurotransmitters lead to adolescents being more emotional, responsive to stress, sensitive to rewards, more likely to engage in sensation seeking
- also more vulnerable to substance abuse and mental health issues
