Ch. 4 - Development & Growth Of The Nervous System Flashcards

1
Q

Nearly all new neurons are generated by when?

A

The end of fetal period and early neonatal period

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2
Q

What are the first two organ systems to function?

A
  1. Cardiovascular

2. Nervous

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3
Q

When does the development in the form of new neural connections occur?

A

T/o the growth ages

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4
Q

Can synaptic developments occur in old age?

A

Yes, with appropriate environmental stimuli

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5
Q

Do neural cells regenerate?

A

No, they are specialized cells that cannot regenerate

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6
Q

When does the total number of neurons start diminishing? Where?

A

Age 20, especially from the cerebral cortex.

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7
Q

Total brain weight decreases:

___% from age 20 - 90

A

10%

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8
Q

How much does nerve conduction velocity decrease?

A

10%

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9
Q

What are the 3 layers of the embryonic disc?

A
  1. Endoderm
  2. Mesoderm
  3. Ectoderm
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10
Q

When does the neural plate form?

A

18 days after conception

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11
Q

What does the neural plate form from?

A

Ectoderm

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12
Q

The neural plate elongates and the lateral edges fold outward to form what?

A

Neural folds

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13
Q

The rostral end of the neural plate enlarges and will later develop into what?

A

The brain

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14
Q

The neural folds continue to grow and eventually meet in the midline beginning in the ________ region to form the ___________ which progresses cephalically and caudally

A

Cervical; neural tube

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15
Q

The entire length of the neural tube is closed by when?

A

25 days

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16
Q

What develops as a bilateral column of cells from the neural ectoderm?

A

Neural crest

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17
Q

What 9 things do neural crest cells develop into?

A
  1. Sensory ganglia
  2. Autonomic ganglia
  3. Enteric ganglia
  4. Pia mater
  5. Arachnoid mater
  6. Sclera of the eye
  7. Neurolemma
  8. Adrenal medullary cells
  9. Carotid body receptors
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18
Q

What are the 4 basic zones (layers) of the neural tube from inside out?

A
  1. Ventricular zone
  2. Subventricular zone
  3. Intermediate (mantle) zone
  4. Marginal zone
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19
Q

Neurons which migrate here will become the gray matter of CNS

A

Intermediate (mantle) zone

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20
Q

Layer of small proliferative cells dividing as primitive neuro lasts which can migrate. Spongioblasts will become astrocytes and oliogodendroglia (myelin makers)

A

Subventricular zone

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21
Q

The most central layer consists of dividing cells which then move out to the next two layers as precursor cells. The cells that remain in this layer are called ependymal cells

A

Ventricular zone

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22
Q

Very few cells; distant axons migrate in /c macroglia to form the white matter

A

Marginal zone

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23
Q

What 2 things are structural organization and function of cells determined by?

A
  1. Intrinsic influences (mostly genetic)

2. Extrinsic influences (mostly environmental)

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24
Q

The predictability of the form and connections of a neuron, and therefore its function; probably genetically determined (including destination of migration, structural characteristics of the cell, characteristic physiological properties of the cell)

A

Neural specificity

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25
Q

Variation from the predictable pattern; probably the result of environmental factors as new synapses and interconnections are established

A

Neural plasticity

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26
Q

What is a very important concept in rehab and in understanding primitive reflexes?

A

Neural plasticity

27
Q

Does the developing or the mature brain exhibit greater plasticity?

A

Developing

28
Q

What neural tube zone becomes the inner gray mater?

A

Intermediate zone

29
Q

What zone of the neural tube becomes the outer white matter

A

Marginal zone

30
Q

What are intermediate zone cells dorsal to the sulcus limit as called? Primarily motor or sensory?

A

Alar plate; sensory

31
Q

What are intermediate zone cells ventral to the sulcus limit as called? Primarily motor or sensory?

A

Basal plate; motor

32
Q

At what month does the spinal cord extend the entire length of the vertebral column?

A

3rd month; and the spinal roots 90 deg.

33
Q

True or False: after the spinal cord stops elongating, the vertebral column continues elongating

A

True

34
Q

At birth, the caudal end of the spinal cord is at ______, in a teen the spinal cord ends at _______

A

L3; L1-L2

35
Q

Each pair of nerves develops in association /c what?

A

Each pair of somites

36
Q

What are somites?

A

Musculoskeletal precursors

37
Q

What does the neural crest become at each level?

A

Paired sensory root ganglion of each spinal nerve

38
Q

What are the 3 dilations that arise from the rostral end of the neural tube by the 3rd week?

A
  1. Prosencephalon
  2. Mesencephalon
  3. Rhombencephalon
39
Q

What does the forebrain originate from?

A

Prosencephalon

40
Q

What does the midbrain originate from?

A

Mesencephalon

41
Q

What does the hindbrain originate from?

A

Rhombencephalon

42
Q

By the ______, the 3 vesicles of brain development become 5

A

2nd month

43
Q

The prosencephalon becomes what 2 structures?

A
  1. Telencephalon

2. Diencephalon

44
Q

What does the telencephalon become?

A

Cortex & basal ganglia

45
Q

What does the diencephalon become?

A

Thalamus & hypothalamus

46
Q

The mesencephalon remains what?

A

The midbrain

47
Q

The rhombencephalon becomes what 2 structures?

A
  1. Metencephalon

2. Myelencephalon

48
Q

What does the metencephalon become?

A

The pons and cerebellum

49
Q

What does the myelencephalon become?

A

The medulla oblongata

50
Q

Develops as an acute bend anterior to the midbrain

A

Mesencephalic flexure

51
Q

Bend that forms on the posterior surface btw the meten- and myelen-cephalon

A

Pontine flexure

52
Q

Bend that develops on the anterior surface at the lower medulla

A

Cervical flexure

53
Q

At what stage in brain development is each brain region recognizable?

A

3 months

54
Q

When in brain development do the fissures begin /c the lateral cerebral fissure and the posterolateral sulcus of the cerebellum

A

4 months

55
Q

When in brain development are all the main gyri and sulci present?

A

7 months

56
Q

When in brain development are all lobes stubby and the insula is still seen on the surface?

A

9th month

57
Q

True or False: in the neonate, the insula is mostly covered by adjacent lobes, and superficial artery are straight

A

True

58
Q

When does the brain reach the relative size and proportions of the adult brain?

A

Age 2

59
Q

A newborn brain weighs _______; ______ by age 1

A

350g; 1000g

60
Q

What is used to measure brain growth in infants and children?

A

Head circumference

61
Q

Brain weight at puberty is how much of body weight?

A

2%

62
Q

Physiological/functional maturation of the nervous system depends upon progressive myelination, especially btw the ___________ and _________

A

3rd trimester; 2 years old

63
Q

True or False: 3/4 of congenital defects involve the nervous system

A

False; 1/2

64
Q

Abnormal development of the brain can be caused by what 4 things?

A
  1. Genetic factors
  2. Nutrition
  3. Hormonal effects
  4. Infections