PSYC 250 1st EditionExam # 2 Study Guide Lectures: 9 - 15Physical Development: Lectures 9 & 10 (September 18th & 23rd)Trends in physical growth- cophalocaudal- direction is from head to tail, head to toes- proximodistal- from torso out, center to extremities o these trends are not absoluteo changes in body proportionso head goes to 50% of length -> 12-13% of length of body in adulthoodo legs go from 25% to 50%- gross motor movemento large muscle groupso will develop 1st, followed by fine motor movements o all motor movement involves the coordination of brain and bodyo fine motor movement o smaller muscles and small muscle groupings Motor milestoneso locomote- move ourselves through space -> leads to more input oo Not every child follows this exact sequence. Some skip steps, add, etc. But the endpoint is the same they all walkFactors contributing to Physical Development1.Maturation: growth of the bone, muscle, connective tissue, nervous systema. changes in the body make It possible for the body to move and be moved in new waysb. maturation is necessary but not sufficientc. sensitive period- window of Time during which body and Brain are most responsive to Experience (greatest plasticity) i. beginning of sensitive period for motor development: prenatal periodii. Ending of sensitive period. Not abrupt/clear cut maybe around 102.Experience: interacting with the environment, practice and encouragementa. childcare practices affect motor development i. augmented practice1. having been made greater in size and value ii. restricted practice 1. doesn't allow the babies to really move or support themselves2. ex. Children born in houses with stairs learn climbing skills sooner, infants born in Denver summer are slower to develop motor skills, back to sleep campaign in us has delayed Upper body motor development bc of less prone position time b. cultural differences i. beliefs, values, and way of life influence childcare practices c. individual differences i. experiences - what infants eat, wear, are held/handled, encouraged, physical environments that either support or hinder movement 3.Dynamical systemsa. curious, motivated, goal driven child actively reorganizes skills to become better at exploring the worldDevelopment of the Nervous System1. Structuresa.glial cells: from word for give, appear to fill in around neurons and hold everything togethera. serve many functions and there are various types. b. Support and transfer nutrients, take up waste, do other things to facilitate neuron communication, impt for metabolic support, wrap around axon to create myelin, aids cell migration, create myelin sheathc. estimated number of glia cells - about 10x as many neuronsb.cell body (soma)-contains nucleus of cellc. dendrites - receive molecules from neurotransmitters from adjacent neurons d.axon - when action potential reaches terminal buttons, molecules of neurotransmitters are released into synapsee.myelin sheath - fatty substance that covers the axon to provide insulation f. neurons - gray matter and white mattera. gray matter - cell bodies and dendrites - parts of the neuron cell not covered in myelinb. white matter - myelinated axon fibers, responsible for communication with other neurons, sequence of events that release neurotransmitters. Myelin covered = more developed2. Developmental processesa. neurogenesis - birth of a neuron, most occurs prenatal in the first 5 months but neurogenesis is still possible in childhood and adulthoodb. synaptogenesis - development of new connections between neurons, growth of dendrites, axons, and terminal buttonsc. increasing ability to communicate --> by growing synapses --> capabilities to sendand receive and respond to messagesd. brain volume rises and then gradually falls with age due to synapse elimination (pruning) and neuron deathe. myelination- myelin wraps around axons aiding function so encouraging system growth 3. Plasticity a. ability to change in response to experience b. brain is plastic through lifea. high through childhood and adolescence c. it demonstrates interaction of internal and external influencesa. experience expectant and Experience dependent Decrease in gray matter from 5 - 20 years oldo somatosensory, olfactory, visual, and motor areas are the most developed at young ageo the visual area develops very rapidly (occipital lobe of the brain) and the somatosensory area (touch)o more white matter equals more mature braino motor and sensory areas myelinate before prefrontal and parietal areaso late adolescence/young adulthood, areas of frontal cortex (areas for response Inhibition, emotional regulation, planning, organization) become more fully myelinated o dorsal lateral prefrontal cortex important for controlling impulses among latest to developBrain deviation in children with ADHDo They lag behind in temporal, and prefrontal areas, especially in areas integrating sensory info with higher order functions like planning and judgment o About 4 years behind on average. Motor areas normal or faster than normal to mature. Their brains do show synaptic growth and myelination Changes in Axonal arbors and synapseso At birth there are many terminal connections between axons and muscle fiberso Development involves pruning, elimination of synapses to make more efficient, focused connection between neurons PubertyWhat starts it?o KiSS1 - gene that causes production of kisspeptin 1.When KiSS1 is activated kisspeptin is produced2.Kisspeptin activates GPR54 gene3.GPR54 causes hypothalamus to produce GnRH4.GnRH causes pituitary gland to produce luteinizing hormone and FSH 5.LH and FSH are sex hormones that stimulate development of ovaries and testes6.development of ovaries and testes leads to a set of hormonal changes that are responsiblefor all notable changes of pubertyo GPR54 - gene that is inactive throughout prenatal development and childhood. When activated causes the hypothalamus to produce gonadotrophin releasing hormone GNRHGrowth Rate in Childhood and Adolescence - Highest growth rate is in prenatal period through about age 3- Then, rate of growth is about steady until onset of puberty - Growth rate is always earlier for girls than boys, across culturesAge of onset for notable events of Puberty:-- Girls:o Breast bud – 10.5o Onset pubic hair – 11o Peak height volume – 11.4o Mesorche – 12.5o Adult breast – 14.6o Adult pubic hair – 13.7- Boys:o Testes volume > 2 – 11.4 o Onset pubic hair – 12o Onset penis growth