Embryology of the Nervous System Flashcards Preview

Neuro Exam 1 > Embryology of the Nervous System > Flashcards

Flashcards in Embryology of the Nervous System Deck (90)
Loading flashcards...
1
Q

notochord

A

iniates entire process of neurulation

signals formation of neural plate (thickened cells)
-dorsal surface of embryo

lateral edges start to fold

2
Q

neural tube

A

formed from fusion of neural tube

3
Q

cranial neuropore closure

A

day 25

4
Q

caudal neuropore closure

A

day 27

5
Q

neural tube

A

forms all of CNS

-brain and spinal cord

6
Q

neural crest cells

A

form just above neural tube

  • from neuroectoderm
  • migrate into underlying mesoderm

become all of the PNS

7
Q

fate of cranial neural crest

A

bones, cartilage, fascia, ligaments and tendons of face, neck

sensory ganglia and autonomic ganglia

8
Q

fate of spinal neural crest

A

dorsal root ganglion
autonomic ganglion
heart - fibrous skeleton

9
Q

shared fate of cranial and spinal neural crest

A

meninges
schwann cells
melanocytes

10
Q

spinal cord formation

A

neural tube caudal to 4th pair of somites forms spinal cord

11
Q

cells of neural tube

A

neuroectoderm

  • migrate out away from lumen
  • establish regions of spinal cord
12
Q

zones of neuroectoderm migration

A

ventricular zone
mantle zone
marginal zone

13
Q

ventricular zone

A

embryo - thick, pseudostratified epithelium called neuroepithelium

adult - simple layer of ependymal cells

14
Q

derivatives of ventricular zone

A

give rise to all neurons and most glia of spinal cord

15
Q

mantle zone

A

zone superficial to the neuroepithelium
composed of neuronal cell bodies
alar and basal plates

forms gray matter

16
Q

sulcus limitans

A

separates basal and alar plates of mantle zone

17
Q

basal plate

A

form motor, ventral horn

18
Q

alar plate

A

form sensory, dorsal horn

19
Q

marginal zone

A

outermost layer
composed of nerve processes (axons/dendrites)

form white matter

20
Q

derivatives of neuroepithelium

A

neuroblasts

gliablasts

21
Q

neuroblasts

A

form ventral horn motor neurons

and dorsal horn sensory neurons

22
Q

gliablasts

A

form astrocytes and oligodendrocytes

23
Q

spinal nerve

A

form from ventral root and dorsal root

24
Q

dorsal root ganglion

A

derived from neural crest

25
Q

microglial cells

A

derived from mesenchymal cells

migrate in later

26
Q

cranial portion of neural tube

A

forms three vesicles

27
Q

prosencephalon

A

forebrain

28
Q

mesencephalon

A

midbrain

29
Q

rhombencephalon

A

hindbrain

30
Q

3 primary vesicles

A

prosencephalon
mesencephalon
rhombencephalon

31
Q

secondary vesicles

A
telencephalon
diencephalon
mesencephalon
metencephalon
myelencephalon
32
Q

derivatives of prosencephalon

A

telencephalon and diencephalon

33
Q

derivatives of rhombencephalon

A

metencephalon and myelencephalon

34
Q

lumen of telencephalon

A

lateral ventricles

35
Q

lumen of mesencephalon

A

cerebral aqueduct

36
Q

lumen of diencephalon

A

third ventricle

37
Q

lumen of rhombencephalon

A

fourth ventricle

38
Q

flexures in brain

A

result of differential growth

cervical - SC to myelencephalon
cephalic - rapid cerebrum growth
-takes place at midbrain
pontine -

39
Q

derivatives of telencephalon

A

cerebral hemispheres

40
Q

derivatives of diencephalon

A

thalamus, hypothalamus, pituitary, optic vesicles, pineal

41
Q

derivatives of mesencephalon

A

midbrain

42
Q

derivatives of metencephalon

A

pons

cerebellum

43
Q

derivatives of myelencephalon

A

medulla

44
Q

lumen of metencephalon and myelencephalon

A

fourth ventricle

45
Q

tela choroidea

A

pia mater + ependymal layer of cells

proliferates and evaginates into ventricles

in roof of third and fourth ventricles
in medial walls of lateral ventricles

46
Q

brainstem vs. spinal cord

A

similar development

  • alar and basal plates
  • alar, dorsal, sensory
  • ventral, vasal, motor

however, gray matter is in distinct nuclei - not columns
-also, sensory nuclei displaced laterally

47
Q

development of myelencephalon

A

forms medulla

get three layers, like in SC

48
Q

pontine flexure

A

lateral flexures

pushes alar plates of myelencephalon laterally

49
Q

order of nuclei in myelencephalon

A

lateral to medial

alar - somatic afferent > SVA > GVA
basal - GVE > SVE > somatic efferent

SA > SVA > GVA > GVE > SVE > SE

    • motor - medial
  • *sensory - lateral
50
Q

CNs of myelencephalon

A

CN VIII, IX, X, XII

8,9,10, 12

51
Q

development of metencephalon

A

forms pons and cerebellum

52
Q

pons development

A

portion of metencephalon

  • three layers like in SC
  • basal - motor
  • alar - sensory

some alar plate cells migrate into white mater
-become nuclei

53
Q

cranial nerves with pons

A

V, VI, VII, VIII

5,6,7,8

54
Q

cerebellum development

A

portion of metencephalon

  • formation of rhombic lip
  • fuse over roof plate
  • form cerebellar plate
  • waves of neuroblasts migrate through marginal layer
  • form outer cerebellar cortex
  • gray matter - external
  • white matter - internal
55
Q

cerebellar plate

A

fusion of rhombic lips

-forms entire cerebellum

56
Q

deep nuclei of cerebellum

A

derived from original marginal layer

57
Q

mesencephalon development

A

forms midbrain
from 3 layers, like SC

basal - motor
alar - sensory

58
Q

CNs of midbrain

A

mesencephalon

III, IV
3, 4

59
Q

roof of diencephalon

A

forms epithalamus

  • contains choroid plexus
  • gives rise to pineal gland
60
Q

alar plates of diencephalon

A

alar plate forms two swellings

superior and inferior

61
Q

superior swelling of alar plate in diencephalon

A

forms thalamus
-bulges into third ventricle

70% of people have interthalamic adhesion form

62
Q

inferior swelling of alar plate in diepcephalon

A

hypothalamus

63
Q

neurohypophysis formation

A

downgrowth of diencephalon neuroectoderm

posterior pituitary

64
Q

adenohypophysis formation

A

upgrowth of oral ectoderm

anterior pituitary

65
Q

optic nerve formation

A

from diencephalon
-evagination of brain

also, most of retina

66
Q

lamina terminalis

A

where the cranial neuropore closes

-in diencephalon

67
Q

radial glial cell

A

act like ladders for neurons in the telencephalon development

to form outer gray cortex

68
Q

new neurons in telencephalon

A

6 waves of cells migrate

-youngest cells most external

69
Q

development of telencephalon

A

two lateral diverticula will form cerebral hemispheres

  • neuroblasts migrate
  • gray - superficial
  • white - deep

also forms corpus striatum

70
Q

neuroblast waves in telencephalon?

A

waves migrate through marginal zone

-along radial glial cells**

71
Q

continued growth of cortex during final part of fetal life

A

gyri - outward convolutions

sulci - fissures

72
Q

corpus striatum formation?

A

swelling within floor of cerebral hemispheres

73
Q

CN of telencephalon

A

olfactor

CN I

74
Q

CN of diencephalon

A

CN II

75
Q

CN of mesenephalon

A

CN III, IV

76
Q

spinal accessory nerve formation

A

from cervical spinal cord

77
Q

spina bifida occulta

A

more common
no neural involvement

only defect in vertebral arch

78
Q

spina bifida cystic

A

more severe
do have neural involvement

meningocele - only meninge
meningomyelocele - meninge and spinal nerve/spinal cord involvement

79
Q

spina bifida

A

neural tube does not fuse posteriorly

-also, vertebral arch does not fuse

80
Q

anencephaly

A

aka meroencephaly
caused by cranial neuropore not closing
-forebrain - does not form
-no di or telencephalon formation

81
Q

craniorachischisis

A

closure defect extends in spinal cord

82
Q

microcephaly

A

small cranium

formed from brain underdevelopment

83
Q

encephalocele

A

failed neural tube fusion and defect in skull
-foramen magnum or lamdoid suture

  • allows portion of CNS to protrude
  • results in cyst-like structure at base of skull
84
Q

meningocephalocele

A

meninges and part of brain bulge through defect

85
Q

meningohydroenephalocele

A

meninges, brain, and part of ventricular system bulge through defect

86
Q

congenital hydrocephalus

A

increased CSF within ventricles

  • imbalance in production and absorption
  • most often obstruction cause

dilation of ventricles proximal to obstruction

skulls expand (sutures not fused)

thin calvaria bone is result

87
Q

Tx for congenital hydrocephalus

A

shunt procedure

cannula into ventricle system

88
Q

common obstuction site for hydrocephalus

A

IV foramina of monro**
cerebral aqueduct of silvius**
lateral apertures of luschka
median aperture of magendie

89
Q

arnold chiari syndrome

A

herniation of cerebellar hemispheres through foramen magnum

  • underdevelopment of posterior cranial fossa
  • skull defect

often associated with spina bifida cystica

type I - congenital

presentation - fingerline projection of cerebellum through the foramen magnum

90
Q

holoprosencephaly

A

rare
failure of forebrain neural tube to form cerebral hemispheres

lateral ventricles fuse