KHA302 Lecture Notes - Lecture 3: Neural Development, Prenatal Development, Plantar Reflex
30 Jun 2018
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KHA302: Lecture 3- 9.3.16
Physical and Motor Development
- Growth graph:
oGeneral, brain and head, reproductive and lymphoid growth all
plateaus at the age of 20
oDifferent rates of maturations in different systems of your own body
oThis has impact on your interaction with the world
oHow you think of yourself and interact in the world
oPhysical growth:
Does not occur at a constant rate
Perceptual, physical ability, ability to think
As these develop interaction with the environment develop
5 months: double birth weight
12 months: triple birth weight, double birth length
24 months: weight and height continue to increase, muscle
replaces fat
physical mechanisms for movement before this is still
limited despite mental capacity
2-6 years: bones harden
ossification
each year after 2: Add on average 5-8cm, 2.5kg
5-8 years: proportions more adult like
get bigger but proportions relatively the same
From 6 years on: longer face, wider mouth
Bottom half of your head is growing down and out
Not the brain and therefore not the top of your head
Jaw grows
Hence why infants eyes seem bigger and lower in the
head than adults
oBaby faces foster attachment:
Large foreheads
Features in lower part of face
Large, round eyes
High and prominent cheeks
These features are attractive to adults and therefore encourages
a social bond
oSize and bodily proportions
The thing that makes us different is the size of our cortex
Head size at birth, compared with other animals, is
massive
Average newborn weighs 3.4kg and 50cm in length
Growth charts show weight and height gain over time
compared to others of same age and sex
oBrain growth and maturation:
At birth, brain is 25% of its adult weight; body is 5% of adult
weight
find more resources at oneclass.com
find more resources at oneclass.com
By age 2, the brain is 75% of adult brain weight, body is 20%
of adult weight
Forebrain, midbrain, hindbrain exist from beginning but
develop and look far different by day 100
Cerebellum
Pons and medulla develop
Folding continues from birth
Cerebral hemisphere increases
oAdolescence: rapid growth spurt
Body becomes ready to reproduce
Secondary sexual characteristics develop
oEarly adulthood: 20-40 (some say 35 year signals end of peak)
Peak of athletic skills
Endurance, strength
oMiddle adulthood: beyond 35/40 years:
Basal metabolism declines
Fat grows easier
oLate adulthood: 65 years inward
Physical changes that have social and psychological impacts
Gradual decrease in:
Muscle tone
Bone density
Joint flexibility
Heart and lung performance
Mobility
Hair whitens (no longer produce myelin)
Skin wrinkles and sags
- Motor development:
oGrowth and development of body movements
Reflexes: motor reaction to a stimulus that does not require
learning
Gross motor skills: crawling, jumping
Fine motor skills: reaching and grasping
oMonitor this because for each of these there is an average age and rate
Deficits in this indicate other underlying deficits
oTwo developmental trends:
Cephalocausal: head to tail
In terms of prenatal growth
Also in terms of our capacity to control our body
The brain grows first, then the head..
Capacity to control movement starts at head and then
goes downward
Proximodistal: near to far
Physical development: central organs first, then limbs
Reaching and grasping this also applies to
- Descriptive approach:
oLong history of describing motor development
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Does not occur at a constant rate. As these develop interaction with the environment develop. 12 months: triple birth weight, double birth length. 24 months: weight and height continue to increase, muscle replaces fat physical mechanisms for movement before this is still limited despite mental capacity. 2-6 years: bones harden ossification each year after 2: add on average 5-8cm, 2. 5kg. 5-8 years: proportions more adult like get bigger but proportions relatively the same. From 6 years on: longer face, wider mouth. Bottom half of your head is growing down and out. Not the brain and therefore not the top of your head. Hence why infants eyes seem bigger and lower in the: baby faces foster attachment: head than adults. These features are attractive to adults and therefore encourages a social bond: size and bodily proportions. The thing that makes us different is the size of our cortex. Head size at birth, compared with other animals, is massive.
