8: Brain Development Flashcards

1
Q

What does the notochordal process induce formation of?

With what molecule?

A

Neural plate

Sonic Hedge Hog (SHH)

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2
Q

When does primary neurulation occur?

A

Day 22-23

Beginning of 4th week

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3
Q

What parts of the CNS form during primary neurulation?

A

Future Brain and lumbar Spinal Cord

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4
Q

What neuropore closes on day 25?

A

Cranial/Rostra Neuropore

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5
Q

What neuropore closes on day 27?

A

Caudal Neuropore

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6
Q

What part of the neural tube forms the brain?

A

Neural tube cranial to 4th somites

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7
Q

What are the three primary brain vesicles?

A
  • Proencephalon: forebrain
  • Mesencephalon: midbrain
  • Rhombencephalon: hindbrain
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8
Q

What primary brain vesicles divide in the 5th week?

A

Forebrain (Prosencephalon)

Hindbrain (Rhombencephalon)

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9
Q

What does the prosencephalon give rise to?

A
  • Telencephalon: cerebral hemipsheres and lateral venticles
  • Diencephalon: thalami structures and 3rd ventricle
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10
Q

What are derivatives from the mesencephalon?

A

Midbrain and cerebral aqueduct

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11
Q

What does the rhombencephalon give rise to?

A
  • Metencephalon: pons, cerebellum, and upper part of 4th ventricle
  • Myelencephalon: medulla and lower part of 4th ventricle
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12
Q

What does the cervical flexure divide?

A

Hindbrain and spinal cord

Flexes forward

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13
Q

What does the pontine flexure divide?

A

Divides hindbrain into rostral metencephalon and caudal myelecephalon (pons/cerebellum and medulla)

Extending

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14
Q

What separates hindbrain from midbrain?

A

Isthmus Rhombencephali

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15
Q

What does the mesencephalic flexure divide?

A

Midbrain and forebrain

Flexes forward

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16
Q

What are some structures formed in the myelencephalon (medulla oblongata)?

A
  • Nuclei Gracilus and Curneatus (sensory nuclei)
  • Pyramids (white matter dealing with motor tracts)
  • Alar and Basal Plates
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17
Q

What gives rise to sensory neurons that remain contained within the CNS?

A

Alar plate

18
Q

What is the embryological origin of motor neurons that leave the CNS to go out to skeletal muscle?

A

Basal plate

19
Q

What is the division between the alar and basal plates?

Which plate is medial and lateral?

A

Sulcus limitans splits alar (lateral) and basal (medial) plates

20
Q

What gives rise to the cerebellum?

A

Dorsal parts of the alar plates

Eventually projects into 4th ventricle and overlaps pons and medulla

21
Q

What coveres teh ependymal roof of the 4th ventricle?

A

Pia Mater

22
Q

What is tela choroidea?

A
  • Very thin part of pia mater that coveres lower part of 4th venticle
  • Will invaginate the ventricle to form choroid plexus
23
Q

How do the median and lateral apertures form?

A

Roof of 4th ventricle evaginates and those ruptures form the aperatures, allowing CSF to enter subarachnoid space

24
Q

What gives rise to the superior and inferior colliculi?

A

Neuroblasts from alar plate that make tectum

Colliculi deal with vision/hearing, which are sensory

25
Q

What gives rise to the tegmental nuclei?

What are some examples of tegmental nuclei?

A

Neuroblasts from basal plate that make tegmental nuclei

  • Red Nuclei
  • Reticular Nuclei
  • CN III Nuclei
  • CN IV Nuclei
26
Q

What gives rise to substantia nigra?

A

Basal or alar plate that migrate ventrally

27
Q

Are diencephalon structures grey or white matter?

A

Grey Matter

28
Q

What gives rise to the hypothalamus?

A

Neuroblasts in intermediate zone

29
Q

What gives rise to the pineal gland?

A

Median diverticulum of the caudal part of the epithalamus

30
Q

What major structure is the caudate nucleus located adjacent to?

A

Lateral ventricle

31
Q

What embryological layer gives rise to the anterior lobe of the pituitary gland?

A

Oral Ectoderm

  • Arises from the stomoedum, leading to Rathke’s pouch
    • Hypophyseal diverticulum
  • When it fuses with posterior pituitary gland, rathke stalk degenerates
32
Q

What embryological layer gives rise to the posterior lobe of the pituitary gland?

A

Neuroectoderm

  • Arises from diencephalon (Neurohypophyseal diverticulum)
  • Infundibulum forms posterior pituitary and infundibular stalk
33
Q

What is holoprosencephaly?

A

Incomplete separation of cerebral hemispheres during development that can result in facial anomalies

34
Q

Patient presents with epilepsy, headache, abnormal movements. Upon examination, he has a reduced frontonasal prominence and a cleft lip as well as some developmental delay. What disorder does he most likely have?

A

Holoprosencephaly

35
Q

What can happen if there is agenesis of corpus callosum?

A

Seizures and mental deficiency

36
Q

What are the layers of the cerebral cortex?

A

From top to bottom:

  • Marginal Zone
  • Intermediate Zone
  • Ventricular Zone
37
Q

Where are the older and newer neurons in the cerebral cortex?

A
  • Older Neurons: Deeper (Layer VI)
  • Newer Neurons: Superificial (Layer I)
38
Q

Failure of neuronal migration during weeks 12-24 can result in what brain disorder?

A

Lissencephaly (agyria, smooth brain)

39
Q

What is Lissencephaly characterized by?

A

Microcephaly

Ventriculomegaly

Minimal operculum of insula

Complete/partial agenesis of corpus collosum

40
Q

What can cause microcephaly?

A
  • Autosomal recessive primary microcephaly
  • Ionizing Radiation
  • Infectious Agents’
    • Cytomegalovirus
    • Rubella
    • Toxoplasma gondii
  • Maternal Alcohol Abuse