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Neuroscience > Embryo: Development of the Nervous System > Flashcards

Embryo: Development of the Nervous System Flashcards

1
Q

Formation of 3 germ layers (endoderm, mesoderm, and ectoderm)

A

Gastrulation

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2
Q

What week does Gastrulation begin?

A

Week 3

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3
Q

Components of gastrulation

A
  • formation of 3 germ layers
  • Primitive streak
  • Notochordal process
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4
Q

What germ layer is the primitive streak made up of?

A

Embryonic ectoderm

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5
Q

3 parts to the primitive streak?

A
  • Primitive node
  • Primitive groove
  • Primitive pit
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6
Q

What region of the embryo does the primitive streak occur at?

A

Caudal region of the embryo

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7
Q

What region of the embryo does the primitive node occur at?

A

Rostral region of the embryo

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8
Q

What germ layer is the notochordal process made of?

A

Mesoderm

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9
Q

What does the notochordal process become?

A

It is the template for formation of the vertebral column and induces the formation of the neural plate

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10
Q

When does neurulation begin?

A

Day 22-23

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11
Q

Notochord induces neural plate formation: ?

A
  • Neural plate
  • Neural groove
  • Neural folds
  • Neural tube
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12
Q

What does the notochord release to form the neural plate?

A

Sonic Hedge Hog (Shh)

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13
Q

What is the neural plate (germ layer)?

A

Thickening of ectoderm

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14
Q

What is the space called when the neural folds have not yet met each other?

A

Neural groove

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15
Q

Neurulation

- In the end, the surface ectoderm becomes?

A

Developing epidermis

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16
Q

Neurulation

  • In the end, the neural crest becomes?
A

Developing spinal ganglion

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17
Q

Neurulation

- When the neural folds met up, it is now called?

A

Neural tube

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18
Q

What are the germ layers involved with the neural plate?

A

Neuroectoderm, surface ectoderm, and neural crest

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19
Q

What germ layer is the neural tube made of?

A

Neuroectoderm

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20
Q

Neurulation

- What day does the rostral neuropore close?

A

Day 25

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21
Q

Neurulation

- What day does the caudal neuropore close?

A

Day 27/28

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22
Q

What does primary neurulation give rise to?

A

Brain and down to the lumbar region of the spinal cord

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23
Q

What day does primary neurulation begin?

A

Day 22-23

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24
Q

What day does secondary neurulation begin?

A

Day 20-42

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25
Q

What is the group of cells from neuroectoderm that forms the sacral and coccyx region of the spinal cord ?

A

Caudal eminence

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26
Q

What are the cells of the nervous system that come from neuroectoderm?

A
  • Dendrite
  • Protoplasmic astrocyte
  • Fibrous astrocyte
  • Oligodendrocyte
  • Ependyma and Epithelium of choroid plexus
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27
Q

What are the cells of the nervous system that come from mesoderm?

A

**Microglial cell

from blood monocytes

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28
Q

Neural tube forms portion of the brain cranial to the ? somites

A

Fourth

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29
Q

What are the three primary brain vesicles?

A
  • Prosencephalon
  • Mesencephalon
  • Rhombencephalon
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30
Q

Prosencephalon is what part of the brain?

A

Forebrain

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31
Q

Mesencephalon is what part of the brain?

A

Midbrain

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32
Q

Rhombencephalon is what part of the brain?

A

Hindbrain

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33
Q

What week do the forebrain and hindbrain divide?

A

5th week

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34
Q

Prosencephalon gives rise to?

A

Telencephalon and

diencephalon

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35
Q

Rhombencephalon gives rise to?

A

Metencephalon and

myelencephalon

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36
Q

What area do we find in the region of the telencephalon?

A

Lateral ventricle

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37
Q

What area do we find in the region of the diencephalon?

A

Third ventricle

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38
Q

What area do we find in the region of the Mesencephalon?

A

Cerebral aqueduct

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39
Q

What is bonded between metencephalon and

myelencephalon?

A

Fourth ventricle

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40
Q

Spinal cord has opening to the ?

A

Central canal

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41
Q

Have ? that give rise the adult formation of the brain

A

Flexures

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42
Q

Telencephalon consists of?

A

Cerebral hemisphere

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43
Q

Diencephalon consists of?

A

Thalamus and hypothalamus

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44
Q

Mesencephalon consists of?

A

Midbrain

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45
Q

Metencephalon consists of?

A

Pons and cerebellum

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46
Q

Myelencephalon consists of?

A

Medulla

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47
Q

Cervical flexure develops in what week?

A

Week 5

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48
Q

Demarcates the hindbrain from the spinal cord

A

Cervical flexure

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49
Q

Divides hindbrain into caudal myelencephalon and rostral metencephalon

A

Pontine flexure

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50
Q

What flexure develops later?

A

Pontine flexure

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51
Q

Bend between midbrain and forebrain

A

Cephalic flexure

persists and gives our brain the adult structure

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52
Q

What week are basal ganglion and cortical structure developing?

A

Between weeks 6 to 32

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53
Q

What is a collection of different cell bodies or nuclei?

A

Basal Ganglion

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54
Q

Basal ganglion includes?

A

Caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra

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55
Q

Telencephalon consists of?

A 
– Cerebral cortex
– ** Subcortical white
matter (including internal capsule) (made of ectoderm) 
– Olfactory bulb and tract
– Basal ganglia
– Amygdala
– Hippocampus
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56
Q

Diencephalon consists of?

A

– ** Thalamus (made of ectoderm)
– Hypothalamus
– Epithalamus
– Eye (optic nerve)

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57
Q

Midbrain consists of?

A

– Cerebral peduncles
– Superior and inferior colliculi
– 2 cranial nerves

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58
Q

Medulla oblongata consists of?

A
  • Olive

- Pyramid

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59
Q

What are the adult structures of the brain?

A
  • Telencephalon
  • Diencephalon
  • Midbrain
  • Cerebellum
  • Pons
  • Medulla oblongata
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60
Q

What results from incomplete separation of cerebral hemispheres?

A

Holoprosencephaly (HPE)

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61
Q

Holoprosencephaly
– Most associated with ?

– Reduction of ?

–Eyes close together aka ?

A
  • facial abnormalities
  • frontonasal prominence
  • Hypotelorism
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62
Q

Causes of Holoprosencephaly

A
  • Genetic and environmental factors
  • Maternal diabetes
  • Teratogens (alcohol) (can cause the cyclopia)
  • Retinoic acid
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63
Q

Clinical features of Holoprosencephaly

A
  • Microcephaly (small head), microphthalmia (small eyes), ocular hypotelorism, midfacial hypoplasia, and cleft lip with or without cleft palate
  • ** Intellectual disability (mental retardation) or developmental delay
  • Epilepsy, hydrocephalus, dystonia, movement disorder, autonomic
    dysfunction, and
    hypothalamic/pituitary dysfunction
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64
Q

Holoprosencephaly spectrum

A
  1. Median cleft lip and palate
    - Mild
  2. Cebocephaly
    - One nose
  3. Ethmocephaly
    - Nose from frontal nasal prominence does not migrate correctly = Probiscus
  4. Cyclopia
    - Most severe
    - Usually die
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65
Q

Pituitary Gland

- First arch ectoderm gives rise to:

A

– Roof of mouth

**– Contributes to anterior lobe of pituitary gland

– Hypophysial
diverticulum (Rathke’s
pouch)

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66
Q

Pituitary Gland

- Posterior lobe of pituitary gland is from?

A

** Neuroectoderm

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67
Q

Posterior lobe of pituitary gland is from neuroectoderm and comes from?

A

– Diencephalic floor

– Neurohypophysial
diverticulum

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68
Q

So the anterior lobe of pituitary is ? and posterior lobe is ?

A
  • Surface ectoderm

- Neuroectoderm

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69
Q

Formation of Spinal Cord and Brain Regions:

Neural tube is caudal or inferior to the ?

A

Fourth pair of somites

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70
Q

Formation of Spinal Cord and Brain Regions:

Neural canal consists of?

A

Central canal (at the center)

71
Q

Formation of Spinal Cord and Brain Regions:

  • Separates alar and basal plates?
A

Sulcus limitans

72
Q

Formation of Spinal Cord and Brain Regions:

• Alar plate

  • Gives rise to ? horn
  • Gives rise to ? neurons that are contained and stay in the CNS
A
  • Dorsal

- Sensory

73
Q

Formation of Spinal Cord and Brain Regions:

• Basal plate
- Gives rise to ? neurons which leave to go out to skeletal muscle

  • Also gives rise to ?
A
  • Motor

- Preganglionic Autonomics

74
Q

Formation of Spinal Cord:

- Zones?

A
  1. Ventricular zone
  2. Intermediate zone (mantle layer)
  3. Marginal zone
75
Q
  • Which zone is gray matte?

- Which zone is white matter?

A
  • Intermediate zone

- Marginal zone

76
Q

Which zone has stem cells that give rise to neurons?

A

Ventricular zone

77
Q

Stem cells give rise ?

A

Ependymoblasts

78
Q

Ependymoblasts give rise to ? and ?

A

Ependymal cells and choroid plexus

- which line the ventricles or central canal

79
Q

Which layer do you get migration of neurons in this area? Formation of neurons, astocytes, microglia.

A

Intermediate zone

80
Q

Which layer has white matter and axon tracts. Axons of neurons leaving. Oligodendrites there and myelinate axons of CNS

A

Marginal zone

81
Q

Pattern Maintained Into Brainstem:

Which ventricle moves structures laterally?

82
Q

Gives rise to dorsal horns and is sensory

A

Alar plate

83
Q

Gives rise to ventral horns and is motor

A

Basal plate

84
Q

Pattern Maintained Into Brainstem:

  • Thinned the roof of the 4th ventricle so have sensory laterally and motor more towards the midline
A

Pontine flexure

85
Q

Pattern Maintained Into Brainstem:

•? - found closest to the midline

  • CN ?
  • Motor neurons going directly to muscles that come from somites are always found in the midline
A
  • GSE

- CN III, IV, VI, XIII (3,4,6,12)

86
Q

Pattern Maintained Into Brainstem:

• Laterally but still in basal plate - have parasympathetic nuclei lateral to ?

87
Q

Pattern Maintained Into Brainstem:

•? - go to pharyngeal arches (CN ?- found laterally)

A
  • SVE

- CN 5,7,9,10

88
Q

Pattern Maintained Into Brainstem:

• Have ? and ? close to sulcus limitans and ? and ? more laterally

A
  • GVA and SVA

- SSA and GSA

89
Q

Myelencephalon

• Alar plate gives rise to: ?

A
  • Cuneate

- Gracile nuclei

90
Q

Myelencephalon:

Cuneate and gracile nuclei are involved with?

A

Proprioception, vibratory sense and 2 point discrimination, and discriminative touch

91
Q

Myelencephalon:

• Basal plate gives rise to: ?

A
  • Hypoglossal nuclei closest to midline
92
Q

Myelencephalon:

• Alar plate gives rise to: ?
extra one

A
  • ** Hypoglossal nucleus
  • ** Dorsal motor vagal nucleus = GVE
  • ** Nucleus Ambiguous = CN 9 and 10
93
Q

Myelencephalon:

• Basal plate gives rise to: ?

A
  • ** Solitary nucleus = gets visceral afferent info
  • Vestibular nuclei
  • Cochlear nuclei
  • Spinal trigeminal tract and nucleus = sensory
94
Q

Metencephalon:

• Basal plate gives rise to: ?

A
  • Abducens nucleus
  • Facial motor nucleus
  • Trigeminal motor nucleus
  • Superior salivatory nucleus
95
Q

Metencephalon:

  • Sulcus limitans gives rise to?
A

Vestibular and cochlear nuclei

96
Q

Mesencephalon:

  • Alar plate germ layer?
  • Basal plate germ layer?
A
  • Ectoderm

- Mesoderm

97
Q

Mesencephalon:

  • Alar plate gives rise to?
A
  • Inferior and superior colliculus (ectoderm)
98
Q

Mesencephalon:

  • Basal plate gives rise to?
A
  • Edinger-Westphal nucleus
  • Red nucleus
  • Oculomotor nucleus and trochlear nucleus

(all mesoderm)

99
Q

Mesencephalon:

• In upper midbrain, anytime you see red nucleus, you also see ? and ?

A

oculomotor and superior colliculus

100
Q

Mesencephalon:

• In Inferior midbrain, you see ?

A

Trochlear nucleus

101
Q

Classifications
•?: somatic muscle

  • ?: autonomics to smooth and cardiac muscle and glands
  • ?: muscles derived from the pharyngeal arches

• ?: sensory in the skin, joint capsule, tendon, muscle
– Ectoderm

• ?:sensory of visceral structures
– Endoderm

  • ? : hearing, balance (CN 8) and sight (CN 2)
  • ? : taste and smell: chemical senses
A
  • GSE (General somatic efferent)
  • GVE (General visceral efferent)
  • SVE (Branchial or Special visceral efferent)
  • GSA (General somatic afferent)
  • GVA (General visceral afferent)
  • SSA (Special somatic afferent)
  • SVA (Special visceral afferent)
102
Q

Ventricles are continuous with the ? in the spinal

cord

A

central canal

103
Q

Location of frontal or anterior horn?

A

Frontal lobe

104
Q

Location of inferior or temporal horn?

A

Temporal region

105
Q

Location of occipital or posterior horn?

A

Occipital region

106
Q

Diseases associated with issues of ventricles?

A
  • Syringomyelia
  • Hydrocephalus
  • Cerebral palsy
107
Q

Kinds of Cerebral Palsy

A
  • Spastic
  • Dyskinetic
  • Ataxic
  • Mixed
108
Q

Cerebral palsy
– Spastic: damage adjacent to the ventricles

– Dyskinetic
•? : damage to the basal ganglion
•? : damage to the basal ganglion and VL thalamus

– Ataxic: damage to the ?

– Mixed

A
  • Athetoid
  • Dyskinetic
  • Cerebellum
109
Q

Cerebral Palsy

- Spastic - damage to the ?

A

cortical spinal tract (motor tract)

spasticity = upper motor neuron issues

110
Q

In homunculus, what is the most medial?

A

Legs and feet

111
Q

Axons come right next to ? ventricles as they descend into the posterior limb of intenral capsule

112
Q

Syringomyelia

  • Excess fluid in the ?
  • Form structures called Syrnx found in vertebral level ?
  • Disease highly associated with ?
  • Causes?
A
  • central canal
  • C2-T9 (but can go higher or lower)
  • Chiari Type 1
  • Some are idiopathic, trauma, infection …
113
Q
  • Too much fluid in the brain
  • Many causes are abnormal development
  • Communicating and obstructive types
A

Hydrocephalus

114
Q

What kind of cerebral palsy?

  • Toe walking and scissor gait (toes pointed in)
  • Hypertone
  • Ventricles enlarge and hit motor tract
115
Q

What kind of cerebral palsy?

  • Slow writhing movements of the extremities and/or trunk
  • Basal ganglia issue
116
Q

What kind of cerebral palsy?

  • Incoordination, weakness and shaking during voluntary movement
  • Drunken sailor gait. Wherever lesion is, falls to that side of the lesion
117
Q

Cerebral Palsy

- Both limbs on one side of body

A

Hemiplegia

118
Q

Cerebral Palsy

- All 4 limbs equally

A

Quadriplegia

119
Q

Cerebral Palsy

- lower limbs more affected than upper limbs

120
Q

Deformity of the hindbrain

A

Arnold-Chiari Malformation

121
Q

Arnold-Chiari type I
• Herniation of ? through foramen magnum

• Usually no symptoms
- Head and neck pain, ? cranial nerves (problems with tongue, facial muscles, lateral eye movements, decreased ?, dizziness, coordinating movements)

A
  • cerebellar tonsils
  • lower
  • hearing

Note:

  • Tongue = hypoglossal
  • Facial muscles = facial n. and exits at pontine medullary junction
  • Lateral eye movement = Abducens at pontine medullary junction
  • Decreased hearing and dizziness = CN 8
  • Coordinating movements/ataxia = Cerebellum
122
Q

Arnold-Chiari type II
• Herniation of ? and ? through foramen
magnum

• ?

• Lower cranial nerves (problems with tongue, facial muscles, lateral eye movements, decreased hearing, dizziness, paralysis
of sternocleidomastoid, coordinating movements)

A
  • Medulla and Cerebellum

- Hydrocephalus

123
Q

Which Arnold-Chiari type doesn’t present until late adolescence and adult hood?

124
Q

Which Arnold-Chiari type presents in infancy or early childhood?

125
Q
  • Which Arnold-Chiari type only has cerebellar tonsils herniating?
126
Q
  • Which Arnold-Chiari type starts with cerebellar tonsils herniating and then picks up vermis?
127
Q

Which Arnold-Chiari type is highly associated with Syringomyelia?

128
Q

Which Arnold-Chiari type present with lower CN problems because traction and compression on these nerves?

129
Q

Which Arnold-Chiari type is almost always associated with spina bifida?

130
Q 
The diagnosis of a
Chiari II malformation
can be made in utero
by fetal MRI, which
demonstrates the
lumbar ?
and cerebral Chiari II
malformation
A

myelomeningocele

131
Q

Dandy Walker Malformation (Cyst):

• Large posterior fossa
cyst continuous with
?

  • Hypoplasia of ?, partial or absence of ?
  • Atresia of ?

• May be associated
with other abnormalities (like GI and heart issues)

A
  • 4th ventricle
  • cerebellum
  • vermis
  • foramina of Luschka and Magendie
132
Q

Dandy Walker Malformation (Cyst):

  • Atresia causing dilation of the ?
A
  • cyst, 3rd ventricle, 4th ventricle and lateral ventricles
133
Q

Dandy Walker Malformation (Cyst) on MRI

A

Cerebellum atrophy and compressed

134
Q

Unknown cause, but thought to be due to obstruction of
blood flow to the areas
supplied by the internal
carotid arteries.

A

Hydranencephaly

135
Q

Hydranencephaly:
• Absences of ? or represented by membranous sacs with
dispersed tissue

• ? is intact

• Excessively head growth
after birth

• ** Little to no cognitive
development

A
  • cerebral hemispheres

- Brainstem

136
Q

At how many months of pregnancy is the cortex smooth?

137
Q

By birth it has the cerebral cortex has folded

in on itself to form ?

A

gyri (bumps) and sulci

grooves

138
Q

At how many months of pregnancy do you get bumps of gyri and grooves of sulci?

A

6-7 months

139
Q

• ? (gyri and sulci) fold over insula

- Formed by ?

A

Operculum

- Formed by frontal, parietal and temporal lobes

140
Q

Cytodifferentiation of Cerebrum:

  • Lamina ? : contains mainly dendrites
141
Q

Cytodifferentiation of Cerebrum:

  • Lamina ? receives the majority of inputs from the thalamus
  • Sensory or motor?
A

IV

  • SENSORY
142
Q

Cytodifferentiation of Cerebrum:

  • Lamina ? projects primarily to the thalamus
143
Q

Cytodifferentiation of Cerebrum:

  • Laminae ? and ? contains mainly neurons that project to other areas of the cortex
A

II and III

144
Q

Cytodifferentiation of Cerebrum: projects mostly to subcortical structures such as the brainstem, spinal cord and basal ganglia

  • Sensory or motor?
145
Q

Cytodifferentiation of Cerebrum:

  • Older areas of the brain have ? layers of cerebrum and newer areas have ? layers
146
Q

Cytodifferentiation of Cerebrum:

Inside-out Sequence: Part 1

A
  • First neurons produced from VENTRICULAR zone
  • Form a superficial layer, the PREPLATE
  • Axons from these neurons and form
    INTERMEDIATE zone
147
Q

Cytodifferentiation of Cerebrum:

Inside-out Sequence: Part 2

A 
- Next neurons to be born migrate into
the middle of the preplate and divide
it into three parts:
• Marginal zone
• Cortical plate
• Subplate
  • Early neurons of the cortical plate will form the deep layers (laminae VI and V) of the finished cortex
148
Q

Cytodifferentiation of Cerebrum:

Inside-out Sequence: Part 3

A

• Later born neurons migrate radially from the ventricular zone across the intermediate
zone and subplate

• Through the earlier layers of VI and V and established laminae IV, then III and finally
II

149
Q

Incomplete of failure of neuronal migration during 12-24 weeks

A

Lissencephaly or Agyria (smooth brain)

smooth brain = mesoderm

150
Q

Lissencephaly or Agyria (smooth brain)

- Characterized by ?

A

– Microcephaly (mesoderm)

– Ventriculomegaly

– Wide Sylvian fissures (mesoderm) and minimal operculum (mesoderm) of insula

– Complete or partial agenesis of the corpus callosum (mesoderm)

151
Q

Lissencephaly or Agyria (smooth brain)

  • Infant have ?, ? or ?
A
  • apnea, poor feeding or abnormal muscle

tone.

152
Q

Lissencephaly or Agyria (smooth brain)

  • Patients later develop ?, ? and ?
A
  • seizures
  • mental retardation
  • mild spastic quadriplegia
153
Q

Microcephaly is a ?, not a

diagnosis

154
Q

2 major mechanisms of Microcephaly

A

– Abnormal or lack of brain development during neurogenesis (mesoderm)

– Injury or insult to a previously normal brain

155
Q

Etiology of Microcephaly

A

– Genetic

– Prenatal and perinatal brain injury
• Cytomegalovirus, rubella,
Toxoplasma gondii

– Craniosynostosis

– Postnatal brain injury

– Unknown

156
Q

Cytodifferentiation of Cerebellum:

  1. Cells from ventricle layer proliferate and migrate and form ? and ? out towards pia
  2. ? - migrates over Purkinje cells and deep cerebellar nuclei cells that have already migrated out
  3. Cells from germination center migrate back in and form ? and ?
A
    • deep cerebellar nuclei
    • purkinje cell layer
    • External germination center
    • granular cells
    • granular layer
157
Q

What germ layer is the cerebellum?

A

Neuroectoderm

158
Q

What vertebral level does the spinal cord end in for a newborn?

159
Q

What vertebral level does the spinal cord end in for a adult?

160
Q

Spinal Cord

  • Neural crest cells give rise to ? and ? in the periphery
A
  • spinal ganglion cells

- sensory neurons

161
Q

Spinal Cord

  • Alar plate gives rise to sensory neurons in ?
  • Neural crest gives rise to sensory neurons in ? (touch, pain, temperature)
A
  • CNS

- Periphery

162
Q

What forms the PNS?

A

Neural crest and ectodermal placode

163
Q

Cells that develop from the

neural crest include:

A

– Neurons of dorsal root
ganglia (sensory)

– Sensory ganglia of cranial nerves (NC)

– Schwann cells (NC)

– Sympathetic ganglia
(Autonomic ganglia- come from NC because post synaptic. Pre = neuroectoderm and post = NC)

164
Q

Development of the PNS

  • Motor: come from ? in the ventral horn or spinal cord
  • Sensory: come from ?
A
  • neuroectoderm

- NC

165
Q

When does myelination form?

A

Late fetal period and continues into first postnatal year

166
Q

What myelinates the CNS?

A

oligodendrocytes

167
Q

What myelinates the PNS?

A

Schwann cells

168
Q

Oligodendrocytes

  • Location?
  • When?
A
  • Start in lower brain stem (myelinate older tracts first and newest last)
  • 6th month through puberty
169
Q

Schwann cells

  • ? roots myelinated before ? roots
  • When?
A
  • Motor before sensory

- 4th month

170
Q

Which lobe of the brain is myelinated last?

A

Frontal Lobe

171
Q

Neural tube disorder where there is failure of closure of CAUDAL neuropore?

A

Spina bifida

  • Note: Occulta closes but closes late and Myelocele doesn’t close at all
172
Q

What can help prevent spina bifida?

A

Folic acid

173
Q

Neural tube disorders where there is failure of closure of ROSTRAL neuropore to close?

A

• Anencephaly
(Meroanencephaly) - (didn’t close at all)

• Encephalocele (with
brain tissue)

• Encephalocele (without
brain tissue)

Neuroscience (14 decks)

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