PSY 220 Chapter Notes - Chapter 5: Lateralization Of Brain Function, Analytic Reasoning, Plantar Reflex
30 Jul 2018
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Chapter 5: Body, Brain, and Health
● Celiac disease - an inherited digestive problem in which gluten (the proteins found in all wheat
products) triggers an immune response that leads to inflammation and damages the small
intestine.
○ Affected children are unable to absorb nutrients from food despite adequate
consumption. If untreated, this disease can lead to malnutrition.
● Endocrine glands - secrete hormones directly into the bloodstream.
○ Pituitary gland - triggers release of hormones from all other endocrine glands by
sending hormonal messages to these glands.
■ Produces growth hormone, which triggers production of specialized hormones
that directly regulate growth.
○ Thyroid gland is important in physical growth and development and the development of
the nervous system.
● Male testes secrete large quantities of testosterone and other male hormones called androgens,
which stimulate growth hormone production and triggers adolescent growth spurt.
● Female ovaries produce large quantities of estrogen and progesterone.
● Throughout the lifespan, the endocrine and nervous systems work together.
● Nervous system consists of CNS (brain and spinal cord) and peripheral nervous system (neural
tissue that extends into all parts of the body).
○ Neurons - the basic unit of the nervous system; a nerve cell.
○ Synapse - the place where one neuron connects with another neuron.
○ Myelination - the depositing of a fatty sheath around neural axons that insulates them
and thereby speeds the transmission of neural impulses. It has numerous implications
for developmental changes across the lifespan.
○ Although neurons differ in size and function, they all have three main parts: the
dendrites, which receive messages from adjacent neurons; the cell body; and the axon,
which sends messages across the synapse to other neurons.
● Cephalocaudal principle - growth occurs in a head-to-tail direction. The head is far ahead of the
rest of the body during the prenatal period. During the first year after birth, the trunk grows the
fastest; in the second year, the legs grow the fastest.
● Proximodistal principle - growth occurs from the center outward to the extremities. It can be
seen during the prenatal period, when the chest and internal organs form before the arms,
hands and fingers.
● Orthogenetic principle - development starts globally and undifferentiated and moves toward
increasing differentiation and hierarchical integration.
● Synaptogenesis - growth of synapses.
● Synaptic pruning - removal of unnecessary synapses.
● Plasticity - the brain is responsive to the individual’s experiences and can develop in a variety of
ways.
○ While it is highly vulnerable to damage, it also can often recover successfully from
injuries.
○ The critical, or sensitive, period for brain development (when it proceeds most rapidly)
is during the late prenatal period and early infancy.
● Size of newborns during the first few months is related more to prenatal experiences
(environment) than to size of parent (genes).
○ Babies grow in fits and starts.
○ Infants whose overall weight gain outpaces gains in height are at risk of childhood
obesity.
● Reflex - an unlearned and involuntary response to a stimulus. Reflexes are important because
they show that the infant’s nervous system is working.
○ Survival reflexes have clear adaptive value (breathing, eye blink, and sucking reflexes).
○ Primitive reflexes are not clearly useful (e.g. Babinski reflex, when infants fan their toes
when the bottoms of their feet are stroked). These reflexes typically disappear during
the early months of infancy.
■ These first appear and then disappear later on -- the presence and absence of
reflexes can serve as a general indicator of neurological health.
● Settling into an organized sleep-wake pattern indicates that the baby is integrating biological,
physiological, and psychosocial information.
○ Newborns spend half of their sleeping hours in active sleep/REM sleep.
○ Infants spend so much time in REM sleep because it is important for their learning and
memory processes.
● Congenital malformations - defects that are present at birth, either from genetic factors or
prenatal events, are the leading cause of death during the first year.
● SES influences health.
● Lateralization - asymmetry and specialization of functions of the two hemispheres of the
cerebral cortex.
○ The left hemisphere controls the right side of the body and is adept at the sequential
processing needed for analytic reasoning and language processing (the thinking side).
○ The right hemisphere controls the left side of the body and is skilled at the simultaneous
processing of information needed for understanding spatial information and processing
visual-motor information, and emotional content of info (the emotional side).
○ The two hemispheres communicate and work together.
○ If one hemisphere is damaged, it may be possible for the other hemisphere to “take
over” the functions lost.
○ Signs of brain lateralization are evident at birth, which suggests it has a genetic basis.
○ We usually tend to rely more on the left hemisphere to control many of our physical
activities.
● Children learn to modify their movements to adapt to changes in environment.
● Children’s health is influenced by parents’ education and SES.
○ Societal influences often inadvertently encourage poor eating habits.
○ More education may mean greater awareness of healthy habits.
○ Children may eat more at home and gain more weight if they are living in a stressful
home situation.
Document Summary
Celiac disease - an inherited digestive problem in which gluten (the proteins found in all wheat products) triggers an immune response that leads to inflammation and damages the small intestine. Affected children are unable to absorb nutrients from food despite adequate consumption. If untreated, this disease can lead to malnutrition. Endocrine glands - secrete hormones directly into the bloodstream. Pituitary gland - triggers release of hormones from all other endocrine glands by sending hormonal messages to these glands. Produces growth hormone, which triggers production of specialized hormones that directly regulate growth. Thyroid gland is important in physical growth and development and the development of the nervous system. Male testes secrete large quantities of testosterone and other male hormones called androgens, which stimulate growth hormone production and triggers adolescent growth spurt. Female ovaries produce large quantities of estrogen and progesterone. Throughout the lifespan, the endocrine and nervous systems work together.
