Developmental

Question 1

Notocord does

Answer 1

Induces overlying ectoderm to differentiate into neuroectoderm and form the neural plate by day 21

And notochord becomes nucleus pulposus of the intervetebral discs

Question 2

Neural plate gives rise to

Answer 2

The neural tube and neural crest cells

Question 3

Alar plate

Answer 3

Dorsal neural tube: give rise to sensory

Question 4

Basal plate

Answer 4

Ventral neutral tube: motor

Question 5

Regional specificiation

Answer 5

Forebrain: prosencephalon
Midbrain: mesencephalon
Hindbrain: rhomboencephalon

Question 6

Prosencephalon becomes

Answer 6

1) telecephalon; cerebral hemishere and lateral bentricle

2) diencephalon: thalamus and third ventricle

Question 7

Mesencephalon becomes

Answer 7

Midbrain and aqueduct

Question 8

Rhombencephalon

Answer 8

1) Metencephalon: pons cerebellum and upper part of 4th ventricle
2) myelencephalon: medulla and lower part of the 4th ventricle

Question 9

When and what to find in neural tube defect

Answer 9

Fail to fuse by 4th week

Increased AFP in aminionic flud and maternal serum
Also increased AChE in aminiotic fluid.

Question 10

Spina bifida occult

Answer 10

Failure of bony spinal canal to close, but no structural herniation+ tuft of hair or skin dimpling at the level of bony defect

Question 11

Meningocele

Answer 11

Meninges but not the spinal cord herniate through the spinal canal defect

Question 12

Meningomyelocele

Answer 12

Meninges and spinal cord herniate through spinal canal defect

Question 13

Forebrain abnormalities: anencephaly

Answer 13

Malformation of anterior neural tube resulting in no brain, open calvariumm (frog like appearance)

Increased AFP, polyhydramniosis

Associated material diabetes,
Reduced risk with folate supplementation

Question 14

Forebrain abnormalities: holoprosencephaly

Answer 14

Failure of left and right hemispheres to separate
Usually during wks 5-6
Complex multifactorial etiology that related to Shh

Moderate form has cleft lip/palate, most severe in cyclopia.

Question 15

Posterior fossa: Chiari II

Arnold Chiari malformation

Answer 15

Cerebellar tonsillar and verminan herniation through foramen magnum with aqueductal stenosis and hydrocephalus

Often presents with thoraco-lumbar myelomeningocele and paralysis below the defect

Question 16

Posterior fossa: Dandy Walker

Answer 16

Agenesis of cerebellar vermis with cystic enlargement of 4th ventricle (fills the enlarged posterior possa)

Associated with hydrocephalus and spina bifida.

Question 17

Syringomyelia

Answer 17

Central cord syndrome
Cystic enlargement of central canal of spinal cord

Cross fibers of spinothalamic tracts typically damaged first

“capek like” bilateral loss of pain and temp sensation in upper extremities (fine touch sensationreserved)

Associated with Chiari I malformation (>3-5 mm crebellar tonsiler ectopia)

Most common atC8-T1

Question 18

Tongue development

Answer 18

Anterior 2/3: 1st branchial arch, sensation via CN5 mandible 3, taste via CN 7.

Poster 1/3: 3rd and 4th arches. sensation and taste mainly via CN 9, and extreme posterior via CN 10

Motor innervation via CN 12, muscles of tones derived from occipital myotomes, except for palatoglossus by CN10