Exam1Lec9DevelopmentofNS Flashcards

1
Q

Where is the neural plate located?
What does the lateral edges become?

A
  • In front of the primitive node (mid dorsal)
  • lateral edges become neural folds
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2
Q

What does notochord and paraxial mescenchyme cause?

A
  • Ectoderm to form to the neural plate
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3
Q

What does the neural tube form?

A

CNS

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4
Q

What does the neural crest form?

A

Forms the PNS and ANS

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5
Q

At week 4, the neural plate forms what? what forms after that

A

forms the neural tube and neural crest cells

Neural tube: CNS

Neural crest cells become: PNS and ANS

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6
Q

What does the cranial 2/3 of the neural plate+ tube become (as far caudal as the 4th pair of somite’s) ⭐️

A
  • Future brain
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7
Q

What does the caudal 1/3 of the neural plate and tube become? ⭐️

A

spinal cord

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8
Q

What gives polarity to the embryo?

A

Primitive streak

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9
Q

For the neural folds, they fuse opposite of _ someite’s

A

4th-6th somite’s

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10
Q
  • What does the fusion of neural folds create?
  • How it is structured?
A

Forming the neural tube that is open at both ends
* Cranial/rostral neuropore
* Caudal neuropore

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11
Q
  • When does the cranial/rostral neuropore close?
  • Caudal neuropore close when?⭐️
A

Cranial/rost NP: around 25 days
Caudal NP: around 27days

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12
Q

What happens during spinal cord development that will decrease the neural canal size?

A

Lateral walls WITH PSEDUO STR COLUMNAR EPITH of the neural tube thickens BUT NOT CENTRAL CANAL

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13
Q

Initially what tissue are the walls of the neural tube composed of?

A

Thick pseudostratified columnar neuroepithelium

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14
Q

For the spinal cord, proliferation and differentiation of the neuroepithelial produces what?

A
  • THick walls
  • thin roof and floor plates

the diff zones

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15
Q

What is the sucus limitans and what does it do ⭐️?

A
  • Differential thickening of lateral walls of the spinal cord produces a shallow longitudinal groove on each side
  • separates alar and basal plate
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16
Q

What does the neuroepithelial cells constitute? ⭐️⭐️⭐️

A
  • Intermediate (mantle zone)
  • Ventricular zone (ependymal cells)
  • Marginal Zone
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17
Q

What does the ventricular zone give rise to? ⭐️

A

macroglial cells and neurons

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18
Q

What does the intermediate (mantle zone) contain and what type of matter? ⭐️

A
  • Contains alar and basal plates
  • Gray matter
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19
Q

What does the marginal zone consist of and what type of matter? ⭐️

A
  • consists of outer parts of the neuroepithelial cells
  • becomes white matter
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20
Q

neuroepithelial calls in the _ zone differeitate into _

A

neuroepithelial calls in the ventricular zone differeitate into primordial neurons- neuroblasts

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21
Q

The alar plate is responsible for _ neurons and forms the _ horn of the spinal cord

A

Sensory; dorsal

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22
Q

How does spinal nerve formation happen?

Dorsal vs ventral

A

Cells from dorsal rami-> spinal nerve_> dorsal root ganglia-> dorsal roots-> dorsal horn

Cells from ventral horn-> ventral roots-> spinal nerve-> ventral rami

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23
Q
  • What is the end of the spinal cord called?
  • Where does it end at in peds and in adults? ⭐️
A

Conus medullaris
* Birth (peds): L3
* Adults: L1-L2

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24
Q

Where are schwann cells derived from?⭐️

A

Dervided from neural crest cells

schwann is PNS

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25
Q

Where do oligodendrocytes dervie from?⭐️

A

Neural tube

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26
Q

⭐️

  • What is a neural tube defect?
  • What are some diseases/issues that arise?
  • What can help to advoid this?
A

failure to close the neural tube
* Spina bifida cystica
* meroencephaly (anenephaly)
* Craniorachischisis

FOLIC ACID FORTIFICATION

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27
Q

What are the two big broad types of spina bifida⭐️

A
  • SB occulta (MOST COMMON)
  • SB cystica (meningeal cysts)
28
Q

What are the different subtypes of SB Cystica ⭐️

A
  • SB meningocele
  • SB meningomyelocel (more common and seere than meningocele)
  • SB myeloschisis (most severe)
29
Q

⭐️

  • What happens in SB occulta?
  • Where is it more common?
  • What is the signs of it?
A
  • Neural arche(s) fail to fuse in the median plane: UNFUSED ARCH
  • at L5 or S1
  • Presents with samll dimple and tufted hair (or lipoma, dermal sinus, etc)
30
Q

What happens in SB Meningomyelocele⭐️

A

MORE COMMON AND SEVERE THAN MENINGOCELE
* Unfused arch
* meninges
* spinal cord

31
Q

What is SB myeloschisis⭐️

A

MOST SEVERE TYPE
* Spinal cord is open
* Neural folds failed to close
* permanent paralysis or weakness in lower limbs

32
Q

What is a good biomarker for spina bifida⭐️⭐️⭐️

A

Alpha-fetaprotein (AFP)

33
Q

What is often associated with severe cases involving several vertebrae?⭐️

A

Meroencephaly
* Absence of the calvaria
* Partial absence of the brain
* Facial abormalitities

34
Q

What is a dermal sinus birth defect⭐️⭐️

A

failure of surface ectoderm to detach from neuroectoderm and meninges that envelop it

Meninges become continous with a narrow channel
* extends to a dimple on the skin in the sacral region

Dimple indicates: region of closure of caudal neuropore
* Last place of separation betwee: surface ectoderm and neural tube

35
Q

When does the caudal neuropore close?⭐️

A

closes roughly at the end of the 4th week

36
Q

The spinal cord ends at _ for newborns and myelination of the ganglion surrounding the spinal cord are due the cells derived from where?

A

L3; Neural crest

37
Q

Develops in the third week when the neural plate and tube are developing from the _

A

neuroectoderm

38
Q

What develops into the brain?⭐️

A

Neural tube, cranial to the fourth pair of somites

39
Q

fustion of the neural folds in the cranial region and closure of the rostral neuropore forms three vesicles:

A
  • forebrain (prosencephalon)
  • midbrain (mesencephalon)
  • hindbrain (rhombencephalon)
40
Q

What does the wall of the neural tube become?⭐️

A

Brain

41
Q

What does the lumen of the tube becomes?⭐️

A

Brain ventricles: CSF formed here

42
Q

Label this⭐️⭐️⭐️

A
43
Q

How does the pituitary gland develop ⭐️⭐️

A

Neurohypohysial Diverticulum (post pit)
* Neuroectodermal downgrowth from diencephalon
* forms neurohypophysis

Hypophysial Diverticulum (ant pit)
* Ectodermal upgrowth from stomodeum
* Forms adenohypophysis (Rathk’e pouch)

44
Q

What does the pontine flexure divide and into what? ⭐️

A

Hindbrain into:
* Metencephalon
-pons
-cerebullum
* Myelencephalon
-medulla

45
Q

The does the pontine flexure also do the ventricle? ⭐️⭐️⭐️

A

Thinning of the roof of the 4th ventricle

46
Q

What special somatic afferents do? ⭐️

A

sense of balance and gravity

47
Q

What plate does special visceral efferent associate with and what does it do?⭐️

A
  • Basal plate
  • Skeletal muscles of branchial arch origin
48
Q

What plate does special visceral afferent associate with and what does it do?⭐️

A

alar plate
“special senses” taste and olfaction

49
Q

What is the ventral and dorsal portion of metencephalon? ⭐️

A

Vent: pons
Dorsal: Cerebellum

50
Q

What does the roof of the 4th venticle contain? How does the CSF flows? ⭐️

A

Choroid Plexus:
CSF flow-> subarachnoid space via three foramina
* foramen of luschka (2)
* Foramen of Magendie (1)

51
Q

Where does the sulus limitans end? ⭐️

A

mesencephalon

52
Q

What does the lumen of the mesencephalon create? ⭐️

A

cerebral aqueduct

53
Q

What does the lateral walls of the diencephalon contain?

A

thalamus, hypothalamus and epithalmus

54
Q

All the nucelei in diencephalon are composed of ?

A

derived alar lamina association cells

55
Q

What does the lumen of the diencephalon create? ⭐️

A

3rd ventricle

56
Q

What is the rostral wall of the 3rd vent formed by?

A

lamina terminalis which is the cranial most end of original neural tube

57
Q

What is the cranial most end of the original neural tube ⭐️

A

lamina terminalis of the 3rd vent

58
Q

What does the telencephalon forms ⭐️

A
  • cerebral hemispheres
  • lateral ventricles
59
Q

What does the telencephalon forms as?

A

lateral diverticula of the orginal neural tube

60
Q

The cerebral hemispheres of the telencephalon, the thinning go walls leads to what?

A

neural tube thins
Leading to the formation of choroid plexus in the:
* floor and medial walls of lateral ventricles
* roof of the 3rd ventricle

61
Q
  • The pontine flexure divides which structure?
  • This structure also contains which ventricle?
A

Hindbrain and 4th ventricle

62
Q

What are the 3 types of craium bifidum (cyst) ?

A

crainial meningocele:
* meninges with CSF

Meningoencephalocele
* meninges with CSF
* Portion of cerebellum

Meningohydroencephalocele:
* meninges with CSF
* Portion of the occipital lobe
* Portion of posterior horn of lateral ventricle

63
Q

What is hydrocephalus?

A

imbalance b/n production and absorption of CSF
* leading to excess CSF in the ventricles

Significan enlargement of the head

Rare cases:
* increased productionof CSF via choroid plexus adenoma

64
Q

What is meroencephaly

A

Defect of calvaria and brain
* failure of the rostral neuropore to close (@ the end of the 4th week)

Forebrain, midbrain, most of the hindbrain and calvaria are absent

Exencephaly
* brain exposed or extruding from the cranium
* nervous tissue degenerates

65
Q

What is microcephaly

A

reduction in brain growth
* without affecting brain structure

Calvaria and brain are small BUT face is normal size

66
Q

What is the corpus callosum

A
  • main neocorical commissure of the cerebral hemispheres
  • Agensis of corpus callosum could lead to brain defects