Neurology - Embryology

Question 1

What is the function of the notochord?

Answer 1

Inducing overlying ectoderm to differentiate into neuroectoderm, and form the neural plate -> give rises to the neural tube and neural crest cells

Question 2

What is the adult remnant of the notochord?

Answer 2

Nucleus pulposus of the intervertebral disc

Question 3

What is the alar plate?

Answer 3

Dorsal: sensory

Question 4

What is the basal plate?

Answer 4

Ventral: motor

Question 5

When is the neural tube formed?

Answer 5

Day 18-21 (3 weeks)

Question 6

What are the three primary vesicles of the developing brain?

Answer 6

Prosencephalon (Forebrain)
Mesencephalon (Midbrain)
Rhombencephalon (Hindbrain)

Question 7

What are the five secondary vesicles of the developing brain?

Answer 7

Telecephalon
Diencephalon
Mesencephalon
Metencephalon
Myelencephalon

Question 8

Adult derivative of: telecephalon

Answer 8

Cerebral hemispheres

Lateral ventricles

Question 9

Adult derivative of: diencephalon

Answer 9

Thalamus

Third ventricle

Question 10

Adult derivative of: mesencephalon

Answer 10

Midbrain (Medulla)

Aqueduct

Question 11

Adult derivative of: metencephalon

Answer 11

Pons and Cerebellum

Upper part of the fourth ventricle

Question 12

Adult derivative of: myelencephalon

Answer 12

Lower part of the fourth ventricle

Question 13

When does neural tube defects occur?

Answer 13

4th week

Question 14

What is neural tube defects associated with?

Answer 14

low folic acid

Question 15

What lab values suggest neural tube defect?

Answer 15

Elevated AFP

Elevated acetylcholinesterase

Question 16

What is a confirmatory test for neural tube defect?

Answer 16

Elevated acetylcholinesterase

Question 17

Spina bifida occulta

Answer 17

failure of bony spinal canal to close
no structural herniation, usually lower vertebral level; dura is intact

associated with tuft of hair or skin dimple

Question 18

Meningocele

Answer 18

Meninges (but not spinal cord) herniate through spinal canal defect

Question 19

Meningomyelocele

Answer 19

Meninges and spinal cord herniate through spinal defect

Question 20

Anencephaly

Answer 20

Malformation of anterior neural tube - no forebrain, open calvarium (frog-like appearance)

Question 21

Lab values for anencephaly

Answer 21

High AFP, polyhydramnios (no swalloing center)

Question 22

What is anencephaly associated with?

Answer 22

materal diabetes (Type I)

Question 23

What can decrease risk of anencephaly?

Answer 23

maternal folate supplement can decrease risk

Question 24

Holoprosencephaly

Answer 24

Failure of left and right hemispheres to separate; usually weeks 5-6

Question 25

What is suggested to be mutated in holoprosencephaly?

Answer 25

sonic hedgehog signaling pathway

Question 26

What are moderate and severe forms of holoprosencephaly associated with?

Answer 26

cleft lip/palate - moderate | cyclopia - severe

Question 27

Cerebral aqueduct stenosis

Answer 27

Accumulation of CSF in ventricular space - most common cause of hydrocephalus in newborns

Question 28

Presentation of cerebral aqueduct

Answer 28

enlarging head circumference due to dilation of ventricles (cranial suture lines not fused)

Question 29

What is dandy-walker malformation?

Answer 29

Congenital failure of cerebellar vermis to develop | Massively dilated 4th ventricle with absent cerebellum often accompanied by hydrocephalus

Question 30

What is dandy-walker associated with?

Answer 30

hydrocephalus and spina bidifa

Question 31

What is arnold-chiari malformation (type II)?

Answer 31

congenital extension of cerebellar tonsils through foramen magnum Obstruction of CSF flow can result in hydrocephalus

Question 32

What is arnold-chiari malformation associated with?

Answer 32

thoraco-lumbar meningomyelocele and syringomyelia

Question 33

What is syringomyelia?

Answer 33

cystic enlargement of central canal of spinal cord

Question 34

What fibers are damaged first in syringomyelia?

Answer 34

Fibers of spinohalamic tract

Question 35

Presentation of syringomyelia

Answer 35

cape-like, bilateral loss of pain and temperature sensation in upper extremities (fine touch is preserved)

Question 36

Where is syringomyelia most common in the spinal cord?

Answer 36

C8-T1

Question 37

Which branchial arch forms the tongue?

Answer 37

1st branchial arch forms anterior 2/3 (sensation V3, taste VII) 3/4 archs form posterior 1/3 (sensation/taste IX, extreme posterior X)

Question 38

What is motor innervation of the tongue?

Answer 38

CNXII

Question 39

What nerves are involved in taste?

Answer 39

Anterior 2/3: VII | Posterior 1/3: IX

Question 40

What nerves are involved in sensation of the tongue?

Answer 40

Anterior 2/3: V3 | Posterior 1/3: IX

Question 41

Muscles of tongue are derived from what?

Answer 41

occipital myotomes