Chapter 6 Flashcards
Babies often double birth weight by _______ months and triple it by ______
4-6
End of first year
Cephalocaudal development:
Sequence of physical maturation and growth that proceeds from the head (cephalic region) to the tail (caudal region)
Proximodistal development:
Sequence of physical saturation and growth that proceeds from the centre of the body (proximal region) to the extremities (distal regions)
Skeletal age:
Measure of physical maturation based on the child’s level of skeletal development.
Variations in physical development:
Different bodily systems display unique growth patterns
Brain and head grow faster than rest of body
Genitals grow slowly through childhood and develop rapidly in adolescence
Growth of lymph issues overshoots adult levels late in childhood, before declining rapidly in adolescence
What accounts for variations in growth?
Heredity plus environmental factors like food, diseases, emotional climate,
Brain growth spurt:
Period between the 7th prenatal month and 2 years of age when more than 1/2 of the child’s eventual brain weight is added
Synapse:
Connective space (juncture) between one nerve cell (neuron) and another
Neurons:
Nerve cells that receive and transmit neural impulses
Glia:
Nerve cells that serve multiple functions including nourishing neurons, encasing them in myelin sheaths, facilitating transport, and waste removal.
Synaptic pruning:
Refinement and elimination of neurons
Starts near time of birth, ends near end of sexual maturation
How do we know that early experience plays dramatic role in development of brain and CNS?
Riesen et al. : Reared infant chimpanzees in the dark; they experienced atrophy of retina and neurons making up optic nerve. Atrophy was reversible if chimps visual deprivation didn’t exceed 7 months. Irreversible and led to total blindness if the deprivation lasted longer than a year.
How do we know enriched environments help?
Animals raised with lots of companions and many toys to play with have heavier brains and display more extensive networks of neural connections than those of litter mates raised under standard lab conditions.
At birth, the most highly developed areas are:
lower (subcortical) brain centres which control states of consciousness, inborn reflexes, and vital biological functions such as digestion, respiration, and elimination.
First areas of cerebrum to mature:
Primary motor areas ( control simple motor activities like waving arms)
Primary sensory areas (control sensory processes like vision, hearing, smelling, tasting.)
Myelinization:
The process by which neurons are enclosed in waxy sheaths that will facilitate the transmission of neural impulses.
Myelinization:
Follows a definite chronological sequence that is consistent with the maturation of the nervous system
Proceeds very rapidly over the first few years of life.
Enhances the efficiency between the more primitive subcortical areas of brain and the more regulatory prefrontal cortical areas
Cerebrum:
The highest brain centre; includes both hemispheres of the brain and the fibres that connect them.
Corpus callosum:
The burden of neural fibres that connect the two hemispheres of the brain and transmit info from one hemisphere to the other.
Cerebral cortex:
The outer layer of the brain’s cerebrum, which is involved in involuntary body movements, perception, and higher intellectual functions such as learning, thinking, and speaking.
