Adolescence: brain development Flashcards
Gray matter
- inverted U shape change
- burst of synaptogenesis, especially in prefrontal cortex
- followed by pruning
- reflects cell bodies and dendrites of neurons
- so increase in early teen and then decrease cause of pruning
White matter
reflects myelinated axons
-develops linearly from childhood (mylenation continues)
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prefrontal cortex
- responsible for planning, inhibition, cognitive flexibility, working memory
- behind foehead
Limbic system
consists of amygdala, hippocampus
- emotional reward system
Asymmetrical development of brain
- the limbic system matures faster than the prefrontal cortex
- limbic is seeking rewards and pleasurable experiences but they don’t have the same prefrontal maturation that helps them control themselves and so tend partake in more rusk taking behaviors
puberty
period of lifespan where an individual becomes capable of sexual reproduction
- developments in endocrine system and nervous system
3 main physical manifestations
- rapid acceleration in growth
- development of primary sex characteristics (gonads)
- development of secondary sec characteristics
endocrin system
produces, circulates and regulates hormone levels in the body
- hormones
- glands
- gonadotropin-releasing hormone neurons (GnRh)
Hypothalamic-pituitary glands (HPG axis)
Hypothalamus releases GnRH homrone that stimulates the pituitary gland which releases LH hormone which tellgonads to release estrogen/testosterone
- theres a set point for how much hormone should be release and when it is reached, GnRH stops releasing.
- this set point varies with age (low in kids)(shuts off easily)
what triggers puberty
- triggered by several environmental and biological factors
- signals tell brain to change the set point of HPG axis
- brain chemical kisspeptin starts the increase of GNRH
- suddenly set point is higher and much more hormones circulate so sexes begin to change
Leptin
- protein released by fat cells
- need to have enough fat in body to stimulate the release of leptin which can stimulate the production of kisspeptin
Adolescent growth spurt
- simultaneous release of growth hormones, thyroid hormones and androgens
- rate spikes to as rapidly as in toddlerhood
sex diferences in muscle and fat
- girls start puberty like 2 years before
- boys end up taller
- beofr puberty not much diffence
tanner stages
stage 1 means no signs yet and stage 5 is that your are done, in between define the different amounts of sex characteristics
Male secondary sex characteristics
- start with growth of penis and scrotum
- emergences of facial and body hair, deepening of voice (later)
- first ejaculation about a year after start of penis growth
