Chapter 4 - Independent Questions
I. Physical Changes
A. The Brain and Nervous System
1. (a) Is the reproductive system fully developed at birth?
(b)What brain structures are the most developed at birth? Identify the functions of these
-midbrain and medulla: regulate vital functions, such as heartbeat, respiration, attention,
sleeping, waking, elimination, movement of head and neck
(c) What part of the brain is the least developed at birth? Identify the functions of this
-cortex (convoluted grey matter): perception, body movement, thinking, language
2. (a) Define the term synaptogenesis, which occurs due to growth of both dendrites and axons.
-synaptogenesis = process of synapse development
3. (b) Define the term synaptic pruning, which occurs because each synaptic growth spurt
generates many more synapses than we actually need.
-synaptic pruning = process by which unused or unnecessary neural pathways and
connections are eliminated
(c) Overtime, the cycle of synaptogenesis followed by synaptic pruning leads to a more
efficient brain. What is the cost or downside of increased efficiency of the brain?
-take longer to bounce back from host of insults to brain (malnutrition, heard injury)
(d) Define the term neuroplasticity – ability of brain to reorganize brain structures in
response to experience
(e) Your textbook states that one of the implications from the cyclical synaptogenesis-
pruning feature of neurological development is that brain development follows the old
dictum “Use it or lose it”. Why do we lose brain functions we don’t use?
- make room for new functions
4. (a) Define the term myelinization – process in neuronal development in which sheaths made
of a substance called myelin gradually cover individual axons and electrically insulate them
from one another to improve the conductivity of the nerve
(b)Although synaptic pruning is influenced by whether or not our synapses are considered
necessary or useful (whether we use the synapse), what influences which neural pathways
are myelinized first?
-cephalocaudal and proximodistal patterns
5. (a) What brain structure
primarily regulates the skill of attention?
(b) When does myelinization of the reticular formation begin and when is it complete?
-begins in infancy, continues in spurts throughout childhood and adolescence, complete in
mid 20s B. Reflexes and Behavioural States
Reflexes (I will expand on this section in the chapter 4 lecture template on adaptive reflexes)
5. (a) What adaptive reflex disappears in infancy or childhood?
-automatically sucking anything that enters mouth
(b) What adaptive reflexes persist across the lifespan?
-withdrawal from painful stimulus, opening/closing of pupil of eye in reponse to
variations in brightness
(c) Compare the purpose of adaptive reflexes to the purpose of primitive reflexes.
-adaptive reflexes aid in survival
-primitive reflexes purposes are less clear; controlled by less sophisticated parts of brain
(b) Identify Philip Zelazo’s research finding about encouraging infants to exercise their
-stimulation of reflexes may facilitate later motor development
-encourage stepping reflex => begin walking at earlier age
-stepping reflex should eventually disappear, otherwise baby has neurological problem
6. (a) How does Bronfenbrenner’s macrosystem context influence the way North American
and European parents respond to their infants’ sleep patterns/problems?
-difference in cultural beliefs
-N.Americans see erratic sleep cycle as a problem and try to ‘fix’ through parents
intervention, try to make baby sleep through night
-European parents see it as normal development and expect babies to acquire normal
sleeping patterns naturally during first 2 years
(b) You hear a mother give her daughter some parenting advice: “Don’t pick up your crying
baby too quickly because it is good to let your baby cry a little first”. Does research support
this mother’s parenting advice? Explain.
-no; research suggests that prompt attention to a crying baby in the first 3 months leads to
less crying later in infancy
C. Developing Body Systems and Motor Skills
7. How do changes in infants’ bones contribute to advances in their motor and manipulative
-bones increase in size, number, composition
-progressive separation of wrist bones increase manipulation skills
-ossification, hardening of bones
-changes in number and density of bones in particular parts of body responsible for
improvements in coordinated movement
8. How do changes in infants’ muscles contribute to advances in their motor skills?
-decrease in fat percentage, water content equal to that of an adult
-changes in muscle composition lead to increases in strength that enable walking, running,
jumping, etc. Lungs and Heart
9. How do changes in infants’ lungs and hearts contribute to advances in their motor skills?
-improvements in lung efficiency and increasing strength of heart muscles result in increase
10. (a) Refer to the sub-heading “Motor Skills” and define the three groups of motor skills:
(1) locomotor skills – also, gross motor skills, include abilities such as crawling; enable
(2) nonlocomotor skills – controlling head movement; improve ability to use senses and
motor skills to interact with objects and people around them
(3) manipulative skills – also, fine motor skills, improve use of hands
(b) James Galloway and Ester Thelen (2004) found an exception to the typical
cephalocaudal and proximodistal pattern of physical development. What did they find?
- babies reach for objects with feet several weeks prior to reaching with hand because legs
more effectively controlled
(c) You need to know the sequence of locomotor, nonlocomoto