Chapter 3/4 Flashcards

1
Q

adaptive reflexes in infancy

A
  • palmar reflex
  • sucking reflex
  • rooting reflex
  • stepping reflex
  • plantar reflex
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2
Q

palmar reflex

A
  • occurs when something is placed in the palm of an infant’s hand and the infant quickly wraps their fingers around the object
  • forces them to practice grasping in order to prepare them to pick of objects
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3
Q

sucking reflex

A
  • occurs when something touches the roof of an infant’s mouth
  • 2 aspects: expression (to express milk from a nipple by pressing it between their tongue and the roof of their mouth) and milking (moving tongue from areola to nipple to coax milk from breast)
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4
Q

rooting reflex

A
  • occurs when anything strokes an infant’s cheek or corner of their mouth -> infant will turn their head towards the side that was touched
  • helps them search for breast b/c they don’t have neck muscles
  • rooting indicates hunger
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5
Q

stepping reflex

A
  • occurs when the soles of an infant’s feet touch a flat surface -> they will life their legs as if they are marching or stepping
  • tries to trigger areas in the brain related to walking
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6
Q

plantar reflex

A
  • infant’s tendency to curl their toes down or away from their shin
  • exercises ability to use feet for grasping, but this goes away because adults don’t reinforce it
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7
Q

what is the purpose of adaptive reflexes in general?

A

they enable infants to perform crucial motor skills which they otherwise wouldn’t be able to do due to insufficient brain development at birth

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8
Q

neuronal proliferation

A
  • rapid production of neurons during the 10th-18th weeks of prenatal development
  • because of this, most fetuses have produced all of their neurons by the 28th week of prenatal development
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9
Q

why can’t babies perform so many motor skills, even if they have all their neurons?

A
  • neurons aren’t tightly packed together -> have synapses/gaps between each other
  • neuron structure must further develop in order to communicate across the gaps
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10
Q

when do neurons consist of cell bodies only?

A

when they’re travelling from the neuron-manufacturing site

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11
Q

dendrites and axons

A
  • allow neurons to form connections with other neurons
  • allow neurons to communicate with other neurons
  • are stimulation-dependent
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12
Q

dendrites

A

bring info from other neurons to the cell body (to receive info from other neurons)

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13
Q

axons

A

take info away from the cell body to other neurons (to send info to other neurons)

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14
Q

synaptogenesis

A

although a few neurons have formed synapses in pre-natal period, this mass production of synapses (dendrite and axon growth) occurs during infancy and toddlerhood

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15
Q

synaptic pruning

A
  • the retraction/elimination of unused synapses

- synapses are activity dependent (need stimulation to survive) - if we don’t use it, we lose it

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16
Q

why are so many synaptic connections eliminated/pruned?

A
  • inactivity (use it or lose it)

- initially the neuron produces a huge over-abundance of synaptic connections

17
Q

advantage of synaptic pruning

A
  • enables neurons to communicate with each other more efficiently (operational efficiency)
  • this efficiency is accomplished due to greater specificity (automaticity) in synaptic connections
18
Q

neuroplasticity

A

brain’s ability to reorganize/regenerate synapses from repeated stimulation/activity (helpful after a stroke, for example)

19
Q

glial cells

A
  • responsible for a lot of brain development in newborns
  • responsible for myelination of axons
  • different from neurons
20
Q

myelination

A
  • improves speed/efficiency of message transfer between neurons
  • most rapid during the first 2 years after birth
  • myelin = fatty substance
21
Q

what 2 major things happen in our brain after birth?

A
  • synaptogenesis (increase in axons and dendrites)

- myelination of axons (increase in number of glial cells)

22
Q

involuntary/voluntary transition period

A
  • involuntary = controlled by reflexes
  • voluntary = adequate brain development to control movement
  • during this period, it’s common to notice a decline in some of an infant’s motor skills
  • ex. grasping skills - infants can grasp objects at 0-1 month, then from 2-3 months they can only swipe them, them at 4-6 months they can voluntarily grab objects
23
Q

3 stages of prenatal development

A
  • germinal
  • embryonic
  • fetal
24
Q

germinal stage

A
  • 1-2 weeks

- conception and implantation in uterine wall

25
Q

embryonic stage

A
  • 3-8 weeks

- organogenesis (creating organ structure)

26
Q

fetal stage

A
  • 9+ weeks

- cell differentiation and growth/development