Embryology

Question 1

What does the Notochord induce?

Answer 1

Overlying ectoderm to differentiate into neuroectoderm & form the neural plate

Question 2

What does the Neural plate give rise to?

Answer 2

Neural tube & neural crest cells

Question 3

What does the Notochord become?

Answer 3

Nucleus pulposus of the intervertebral disc in adults

Question 4

What is the Alar plate?

Answer 4

Dorsal & Sensory

Question 5

What is the Basal plate?

Answer 5

Ventral & Motor

Question 6

What is the forebrain?

Answer 6

Prosencephalon

Question 7

What is the Midbrain?

Answer 7

Mesencephalon

Question 8

What is the Hindbrain?

Answer 8

Rhomobenchephalon

Question 9

Which secondary vesicles does the Prosencephalon become?

Answer 9

Telencephalon & Diencephalon

Question 10

Which 2° vesicles does the Mesencephalon become?

Answer 10

Mesencephalon

Question 11

Which 2° vesicles does the Rhombencephalon become?

Answer 11

Metencephalon & Myelencephalon

Question 12

What are the adult derivatives of Telencephalon?

Answer 12

Walls: Cerebral hemisphere

Cavities: Lateral ventricles

Question 13

What are the adult derivatives of Diencephalon?

Answer 13

Walls: Thalamus

Cavities: Third ventricle

Question 14

What are the adult derivatives of Mesencephalon?

Answer 14

Walls: Midbrain

Cavities: Aqueduct

Question 15

What are the adult derivatives of the Metencephalon?

Answer 15

Walls: Pons & Cerebellum

Cavities: Upper part of 4th ventricle

Question 16

What are the adult derivatives of the Myelencephalon?

Answer 16

Walls: Medulla

Cavities: Lower part of 4th ventricle

Question 17

When do Neural Tube Defects occur?

Answer 17

Neuropores fail to fuse in the 4th week

Question 18

What is a Neural Tube Defect?

Answer 18

Persistent connection b/w amniotic cavity & spinal canal

Question 19

What are Neural Tube Defects assoc w/?

Answer 19

Low folic acid intake before conception & during pregnancy

Question 20

What labs indicate a Neural Tube Defect?

Answer 20

• Inc AFP in amniotic fluid & maternal serum
• Inc AChE in amniotic fluid (confirmatory test)

Question 21

What is Spina bifida occulta?

Answer 21

Failure of bony spinal canal to close, but no structural herniation. Dura is intact

Question 22

Where is Spina bifida usually located?

Answer 22

Lower vertebral levels

Question 23

What is Spina bifida assoc w/?

Answer 23

Tuft of hair or skin dimple at level of bony defect

Question 24

What is Menigeocele?

Answer 24

Meninges (but not SC) herniate through spinal canal defect

Question 25

What is Meningomyelocele?

Answer 25

Meninges & SC hernicate through spinal canal defect

Question 26

What are the forebrain anomalies?

Answer 26

Anencephaly & Holoprosencephaly

Question 27

What is Anencephaly?

Answer 27

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

Question 28

What are the clinical findings in Anencephaly?

Answer 28

* Inc AFP * Polyhydraminos (no swallowing center in brain)

Question 29

What is Holoprosencephaly?

Answer 29

Failure of left & right hemispheres to separate

Question 30

When does Holoprosencephaly occur?

Answer 30

Weeks 5-6

Question 31

What causes Holoprosencephaly?

Answer 31

Complex multifactorial etiology that may be related to mutations in sonic hedgehop signaling pathway

Question 32

What is the moderate form of Holoprosencephaly?

Answer 32

cleft lip/palate

Question 33

What is the most severe form of Holoprosencephaly?

Answer 33

Cyclopia

Question 34

What is Anencephaly assoc w/?

Answer 34

Maternal Type I diabetes

Question 35

What dec the risk of Anencephaly?

Answer 35

Maternal folate supplementation

Question 36

What are the Posterior fossa malformations?

Answer 36

Chiari II (Arnold-Chiari malformation) & Dandy-Walker

Question 37

What is Chiari II (Arnold-Chiari malformation)?

Answer 37

Significant cerebellar tonsillar & vermian herniation through foramen magnum w/ aqueductal stenosis & hydrocephalus

Question 38

How does Chiari II (Arnold-Chiari malformation) present?

Answer 38

Thoraco-lumbar myelomeningocele & paralysis below the defect

Question 39

What is Dandy-Walker malformation?

Answer 39

Agenesis of cerebellar vermis w/ cystic enlargement of 4th ventricle (fills the enlarged posterior fossa)

Question 40

What are Dandy-Walker malformations assoc w/?

Answer 40

Hydrocephalus & spina bifida

Question 41

What is Syringomyelia?

Answer 41

Cystic enlargement of central canal of spinal cord

Question 42

What is usually damaged first in Syringomyelia?

Answer 42

Crossing fibers of spinothalamic tract

Question 43

What does Syringomyelia result in?

Answer 43

"Cape-like" bilateral loss of pain & temp senstation in UE (fine touch sensation is perserved)

Question 44

What is *Syrinx*?

Answer 44

Tube as in syringe

Question 45

What is Syringomyelia assoc w/?

Answer 45

Chiari I malformation (\>3-5mm cerebellar tonsillar ectopia)

Question 46

What location is Syringomyelia MC in?

Answer 46

C8-T1

Question 47

Which brachial arch form the anterior 2/3 of the tongue?

Answer 47

1st brachial arch

Question 48

Which cranial nerve does sensation for anterior 2/3 of the tongue?

Answer 48

CN V₃

Question 49

Which cranial nerve does taste for anterior 2/3 of the tongue?

Answer 49

CN VII

Question 50

Which brachial arches form the posterior 1/3 of the tongue?

Answer 50

3rd & 4th brachial arches

Question 51

Which cranial nerve controls sensation & taste of the posterior tongue?

Answer 51

CN IX | (extreme posterior CN X)

Question 52

Which cranial nerve controls motor innervation of the tongue?

Answer 52

CN XII

Question 53

What are the muscles of the tongue derived from?

Answer 53

Occipital myotomes