2. I. BODY GROWTH
A. Changes in Body Size and Proportions
• 1. On the average, 2 to 3 inches in height and about 5
pounds in weight are added each year.
• 2. The child gradually becomes thinner; girls retain
somewhat more body fat, whereas boys are slightly more
muscular.
• 3. Posture and balance improve, resulting in gains in motor
coordination.
• 4. Individual differences in body size are even more
apparent during early childhood than in infancy.
• 5. To determine if a child's atypical stature is a sign of a
growth or health problem, the child's ethnic heritage must
be considered.
3. B. Skeletal Growth s in which cartilage
• 1. Between ages 2 and 6, approximately 45
epiphyses, or new growth center hardens into
bone, emerge in various parts of the skeleton.
• 2. X-rays permit doctors to estimate children's
skeletal age, the best available measure of
progress toward physical maturity.
• 3. By the end of the preschool years, children
start to lose their primary teeth.
4. II. BRAIN DEVELOPMENT
A. Synaptic Growth and Pruning
• 1.Brain metabolism reaches a peak around 4 years of age. By this
time, many cortical regions have overproduced synapses, which
results in a high energy need.
• 2. The overabundance of synaptic connections is believed to play a
role in the plasticity of the young brain.
• 3. Synaptic pruning occurs as neurons that are infrequently
stimulated lose their connective fibers and the number of synapses
is reduced. This process is adaptive.
• 4. A surprising feature of brain development is that rapid bursts of
synaptic growth are accompanied by high rates of cell death in
order to make room for the connective structures of active neurons.
• 5. Plasticity is reduced by ages 8 to 10, and energy consumption of
most cortical regions declines to near-adult levels.
5. B. Lateralization
• 1.The two hemispheres of the cortex develop at
different rates.
• 2. The left hemisphere shows dramatic activity
between 3 and 6 years and then levels off.
• 3. Activity in the right hemisphere increases
slowly throughout early and middle childhood,
showing a slight spurt between ages 8 and 10.
• 4. Differences in rate of development of the two
hemispheres suggest that they are continuing to
lateralize .
6. C. Handedness
• 1.By age 2, hand preference is fairly stable, and it strengthens
during early and middle childhood.
• 2. The dominant cerebral hemisphere is the hemisphere
responsible for skated motor action. The left hemisphere is
dominant in right-handed individuals. In left-handed individuals,
motor and language skills are often shared between the
hemispheres.
• 3. The brains of left-handers tend to be less strongly lateralized than
those of right-handers. Many left-handers are ambidextrous.
• 4. New evidence indicates that the way most fetuses lie in the
uterus-turned toward the left- may promote greater postural
control by the right side of the body.
• 5. Left and mixed-handed children are more likely than their right-
handed age mates to develop outstanding verbal and mathematical
talents.
7. • D. Other Advances in Brain Development
• 1. The cerebellum is located at the rear and base of the
brain and aids in balance and control of body
movement.
• 2. The fibers linking the cerebellum to the cerebral
cortex do not complete myelinization until about age 4.
• 3. The reticular formation maintains alertness and
consciousness; it myelinates throughout early
childhood and continues growth into adolescence.
• 4. The corpus callosum is the large bundle of fibers that
connects the left and right hemispheres. Myelinization
does not begin until the end of the first year of life, but
is fairly advanced by age 4 to 5.
8. III. FACTORS AFFECTING GROWTH and HEALTH
• Heredity and Hormones
– 1. Children's physical size and rate of growth are related to
that of their parents.
– 2. The pituitary gland is a gland located near the base of
the brain that releases hormones affecting physical
growth.
a. Growth hormone affects the development of almost
all body tissues, except the central nervous system and the
genitals. Short children with GH deficiency can be treated
with injections of genetically engineered GH.
b. Thyroid stimulating hormone stimulates the thyroid
gland to release thyroxin, which is necessary for normal brain
development and body growth.
9. IV. MOTOR DEVELOPMENT
A. Gross Motor Development
• 1. As children's bodies become more streamlined and less top-
heavy, their center of gravity shifts downward toward the trunk
and, as a result, their balance improves.
• 2. By age 2, the preschooler's gait becomes smooth and rhythmic,
leading to running, jumping, hopping, galloping, and skipping.
• 3. As children become steadier on their feet, their arms and torsos
are freed to experiment with new skills-throwing and catching balls,
steering tricycles, and swinging on horizontal bars and rings
10. • 4. Five-year-olds run about twice as quickly as they did at age 2.
Around age 4, gallops and one-step skips appear, and around age 6,
children can skip in a well-coordinated manner.
• 5. The first jumps appear around age 2. During the middle of the
third year, the first two- foot takeoffs and landings can be seen.
Between ages 2 and 3, children can hop a few times in succession,
and 5- and 6-year-olds can hop skillfully.
•
6. At ages 2 and 3, catching and throwing are awkward and stiff.
Gradually, children use their shoulders, torso, trunk, and legs to
support throwing and catching; consequently, the ball travels faster
and further.
11. B. Fine Motor Development
• 1. Self-Help Skills:
a. During early childhood, children gradually become self-sufficient at dressing and
feeding.
b. Shoe tying, mastered around age 6, requires a longer attention span, memory
for an intricate series of hand movements, and the dexterity to perform them.
• 2. Drawing and Writing:
a. As the young child's ability to mentally represent the world expands, marks on
the page take on definite meaning.
b. From Scribbles to Pictures:
1) Scribbles- Western children begin to draw during the 2nd year. At first,
action, rather than the scribble itself, contains the intended message.
2) First Representational Shapes and Forms-By age 3, scribbles start to
become pictures. Use of lines to represent object boundaries permits children to
draw their first pictures of a person by age 3 or 4.
3) More Realistic Drawing5-More conventional figures, in which the body is
differentiated from the arms and legs, appear by age 6.
12. • However, drawings at this age still contain perceptual
distortions, such as a missing third dimension.
c. Cultural Variations in Development of Drawing
1) Children's drawings reflect the interest in art
demonstrated by other members of their culture. Children
in cultures with little interest in art produce simpler forms.
2) Schooling provides opportunities to draw and write,
see pictures, and grasp the notion that artistic forms have
meanings shared by others.
d. Early Printing:
1) As young children experiment with lines and
shapes, notice print in picture books, and observe people
writing, they try to print letters and, later on, words.
2) Often the first word printed is the child's name.
13. C. Individual Differences in Motor Skills
• 1. Body build influences gross motor abilities.
• 2. African-American children tend to have longer limbs, so
they have better leverage in running and jumping than do
Caucasian children.
• 3. Boys are slightly ahead of girls in skills that emphasize
force and power.
• 4. Girls have a slight edge in fine motor skills and in certain
gross motor skills that require a combination of good
balance and foot movement, such as hopping and skipping.
• 5. Social pressure for boys to be active and physically skilled
and for girls to play quietly at fine motor activities may
exaggerate small, genetically based differences.
14. D. Enhancing Early Childhood Motor Development
• 1 Except for throwing, there is no evidence that
preschoolers exposed to formal lessons are
ahead in motor development.
• 2. Preschools, day care centers, and playgrounds
need to accommodate a wide range of physical
abilities by offering a variety of pieces of
equipment that differ in size or that can be
adjusted to fit the needs of individual children.
• 3. Criticism of a child's motor performance,
pushing specific motor skills, and promoting a
competitive attitude may undermine young
children's motor progress.
