Physical Development in Infants/Toddlers 1 Flashcards
cephalocudal trend
during the prenatal period the head develops more rapidly than the lower part of the body
proximodistal trend
growth proceeds from the center of the body outward
Why does baby fat peak and when does it decrease?
- to help infant maintain a constant body temperature
- in the second year
What are the sex differences in body size and physical development?
- in infancy girls are slightly shorter and lighter than boys, with a higher ratio of fat to muscle
- girls are considerable ahead of boys in skeletal age and in development of other organs
Why does the skull grow so rapidly from birth to 2 years?
large increases in brain size
fontanels
the six gaps, or soft spots, separating the bones of the skull at birth
neurons
nerve sells that store and transmit information
synapses
tiny gaps where fibers from different neurons come close together but do not touch
neurotransmitters
chemicals released by neurons that send messages to one another by crossing the synapse
What is the function of fontanels?
they permit the bones to overlap as the large head of the baby passes through the mother’s narrow birth canal
How many neurons does the brain have?
100 to 200 billion
Why is stimulation vital to the survival of neurons?
neurons that are stimulated by input from the surrounding environment continue to establish new synapses, forming increasingly elaborate systems of communication that support more complex abilities
synaptic pruning
neurons that are seldom stimulated and not needed at the moment to an uncommitted state so they can support future development
glial cells
make up about half of the brain’s volume and are responsible for myelination
myelination
the coating of neural fibers with an insulating fatty sheath
How many synapses are pruned during childhood and adolescence?
40%
What is the purpose of myelination?
it improves the efficiency of message transfer
How much does the brain grow from birth to age 2?
from 30% of its adult weight to 70%
cerebral cortex
- surrounds the rest of the brain
- largest brain structure
- account for 85% of the brain’s weight
- contains the greatest number of neurons and synapses
When do auditory and visual areas of the brain experience a burst in growth? When does the language area?
- over the first year
- late infancy through the preschool years