Human Development - Lifespan (Infancy)
Chapter 3: Infancy
Module 3.1: Physical Development in Infancy
Looking Ahead
Growth and Stability
An Interesting Head Count
Are there gender and ethnic differences in infant weight and length?
Principles of Growth
Cephalocaudal principle
Proximodistal principle
Principle of hierarchical integration
Principle of independence of systems
Nervous System and Brain
Nervous system comprises the brain and the nerves that extend throughout the body
Neurons are the basic cells of the nervous system
Quick Check
Neurons
Dendrites
Axons
Neurotransmitters
Synapses
How great brains grow!
Birth:
100-200 billion neurons Relatively few neuron-neuron connections
During first two years: Billions of new connections established and become more complex Use it or lose it!
Synaptic pruning
Unused neurons are eliminated
Allows established neurons to build more elaborate communication networks with other neurons Development of nervous system proceeds most effectively through loss of cells
Myelin
Form and Function: Brain Growth
Neurons reposition themselves with growth, becoming arranged by function
Cerebral cortex
Subcortical levels
Environmental Influences on Brain Development
Plasticity
Sensitive period What do babies do all day?
Life Cycles of Infancy
Wake
Defecate
Sleep
Eat
Rhythms and States
State
One of major body rhythms
Degree of awareness infant displays to both internal and external stimulation
Change in state alters amount of stimulation required to get infant’s attention
Sleep: Perchance to Dream
Major state
16-17 hours daily (average); wide variations
Different than adult sleep
2 hour spurts; periods of wakefulness
Cyclic pattern
By 16 weeks sleep about 6 continuous hours; by 1 year sleep through night
(See table 3-2)
REM Sleep
Period of active sleep
Closed eyes begin to move in a back-and-forth pattern
Takes up around one-half of
Module 3.1: Physical Development in Infancy
Looking Ahead
Growth and Stability
An Interesting Head Count
Are there gender and ethnic differences in infant weight and length?
Principles of Growth
Cephalocaudal principle
Proximodistal principle
Principle of hierarchical integration
Principle of independence of systems
Nervous System and Brain
Nervous system comprises the brain and the nerves that extend throughout the body
Neurons are the basic cells of the nervous system
Quick Check
Neurons
Dendrites
Axons
Neurotransmitters
Synapses
How great brains grow!
Birth:
100-200 billion neurons Relatively few neuron-neuron connections
During first two years: Billions of new connections established and become more complex Use it or lose it!
Synaptic pruning
Unused neurons are eliminated
Allows established neurons to build more elaborate communication networks with other neurons Development of nervous system proceeds most effectively through loss of cells
Myelin
Form and Function: Brain Growth
Neurons reposition themselves with growth, becoming arranged by function
Cerebral cortex
Subcortical levels
Environmental Influences on Brain Development
Plasticity
Sensitive period What do babies do all day?
Life Cycles of Infancy
Wake
Defecate
Sleep
Eat
Rhythms and States
State
One of major body rhythms
Degree of awareness infant displays to both internal and external stimulation
Change in state alters amount of stimulation required to get infant’s attention
Sleep: Perchance to Dream
Major state
16-17 hours daily (average); wide variations
Different than adult sleep
2 hour spurts; periods of wakefulness
Cyclic pattern
By 16 weeks sleep about 6 continuous hours; by 1 year sleep through night
(See table 3-2)
REM Sleep
Period of active sleep
Closed eyes begin to move in a back-and-forth pattern
Takes up around one-half of