Puberty

Puberty

1. Adolescence

   • Biologically-initiated (puberty) and socially-terminated (with adult roles)

2. Why cool

   • not random
     • follows a prescribed sequence of events (same neural regions, same hormones) in every individual)
     • always initiated in adolescence (not in toddlers, college students, older adults)
     • means that over evolutionary time all species have determined the optimal developmental time for sexual maturation (e.g. human puberty well before adulthood)

3. Long process influenced by many factors

   • Metamorphosis
     • under hormonal control
     • abrupt change in body structure (height, weight, and shape)
     • change in behavior and mood
     • although humans don't, puberty share common characteristics
   • pubertal hormones
     • released in the brain
     • Gonadotropin releasing hormone (GnRH)
       • the main hormone that jumpstarts puberty
       • released from the GnRH neurons in the hypothalamus
         • only 1000-3000 GnRH neurons in mammals
           • relatively few for a typical type of neuron--> must have important function for brain to retain them
         • two different roles
           • Organizational role
             • prenatal: help differentiate sex difference in brain
           • Activational role
             • puberty: release other hormones
             • What "reawaken" GnRH?
               • internal and external cues trigger GnRH
                 • internal
                   • genetic factor
                     • girls menstrual similar to mother and sisters
                   • ethnicity
                     • minority boys and girls tend to undergo puberty earlier
                 • external
                   • stress
                     • more stress, puberty early
                       • evolutionary
                   • home composition
                     • w/o biological father-->puberty earlier
                   • diet
                     • gain certain amounts of weight important for onset
                 • developmental clock
                   • innate clock that times the unfolding of primary genetic programs
                 • on one factor is responsible
                   • integrator is unknown--> hard to predict puberty
       • changes the meaning of sensory information (sight/smell/touch/hearing)
         • affects regions of the brain paying attention to sensory information
         • adult female means one thing to a pup and another to an adult male
       • triggers the secretion of the hormones LH/FSH
         • LH (Luteinizing hormone)
           • controls testosterone production in males and estrogen secretion in females
             • secondary sex characteristics
         • FSH (follicle stimulating hormone)
           • stimulates sperm production in males and follicle development in females
             • elements required to be sexually mature
         • Negative feedback loop controls the amount of hormone
   • different stages
     • Tanner 1-5
     • Adrenarche
       • ~6-8 early stage, rising hormone levels w/o visible external physical changes-oiliness in skin, body odor, pubic hair
     • Gonadarche
       • ~8-10 growth spurt/first menstrual, ejaculation
     • Menarche
       • secondary sex characteristics emerge
       • least ambiguous but not a good proxy for onset of puberty because it occurs relatively late
     • no single age--> mostly ~9-16

4. timing

   • greater difference in menarche and thelarche(breast development)
   • Delayed pubertal onset
     • Malnourished
     • Anorexic
     • High physical activity(athletes)
     • implications on behavior
       • be more successful psychosocially
       • have better academic and other outcomes
   • Early pubertal onset
     • Obese
     • reared in stressful environments
     • poor family relationships
     • implication on behavior
       • girls
         • more likely smoke/drink/disordered eating/depressive/low self-esteem
         • be sexually promiscuous
         • conflict with parents, have older friends
       • boys
         • higher frequency of internalizing symptoms
           • depression, worry, fear, self-injury, and social withdrawal
         • externalizing symptoms
           • aggression, law-breaking. or hyperactivity

5. other physical growth

   • weight
   • height
     • girls-3.5 inches/year;boys ~4 inches/year
   • bone age
     • closing of gap at epiphysis--> end of puberty

Bilder und Dateien der Mindmap