CNS embryology

Question 1

Which organelle becomes hypertrophied in hepatocytes with chronic phenobarbital use

Answer 1

Smooth ER

Question 2

The forebrain (prosencephalon gives rise to what?

Answer 2

• Telencephalon —> cerebral hemispheres

- Diencephalon –> thalamus

Question 3

The midbrain (mesencephalon gives rise to what?

Answer 3

-mesencephalon —> mid brain

Question 4

The hindbrain (rhombencephalon) gives rise to what?

Answer 4

• metencephalon –> pons

- Myelencephalon –> medulla

Question 5

On a Quad screen in pregnancy, what should be expected if you have elevated AFP

Answer 5

• Neural tube defects

- Anterior abdominal wall defect

Question 6

On a Quad screen in pregnancy, what should be expected if you have Low AFP

Answer 6

Down syndrome

Question 7

Describe a chiari malformation

Answer 7

herniation of cerebellar tonsils

-may cause syringomyelia

Question 8

Describe a Dandy Walker syndrome

Answer 8

• Enlarged posterior fossa
• Cerebellar vermis fails to develop
• Dilation of 4th ventricle

Question 9

Dandy Walker syndrome is associated with what?

Answer 9

• hydrocephalus

- Spina bifida

Question 10

What are 3 causes of holoprosencephaly

Answer 10

• Fetal alcohol syndrome
• Sonic hedgehog mutation
• Trisomy 13 (patau)

Question 11

Pharyngeal cleft is from what cell derivative?

Answer 11

Ectoderm . . . both C’s

Question 12

pharyngeal Pouch is from what cell derivative?

Answer 12

Endoderm

Question 13

Pharyngeal Arch is from what cell derivative?

Answer 13

Mesoderm . . Mesoderm bridges the gap b/t endo and ectoderm —-> and Arch bridges a gap

Question 14

what comes from 1st pharyngeal CLEFT?

Answer 14

external auditory meatus

Question 15

What do 2nd, 3rd, and 4th pharyngeal CLEFTS give rise to

Answer 15

• temporary cervical sinuses

- could fail to obliterate —> pharyngeal cleft cyst on LATERAL neck

Question 16

What does 1st Pharyngeal POUCH give rise to

Answer 16

• middle ear cavity
• Eustachian tubes
• Mastoid air cells

Question 17

What does 2nd pharyngeal POUCH give rise to

Answer 17

Epithelial lining of tonsils

Question 18

What does 3rd pharyngeal POUCH give rise to

Answer 18

• INFERIOR PARATHYROID glands

- thymus

Question 19

What does 4th pharyngeal POUCH give rise to

Answer 19

SUPERIOR parathyroid

Question 20

Cartilage for 1st pharyngeal Arch?

Answer 20

• M’s and T’s
• Meckel’s cartilage
• Mandible
• Mandibular ligament
• Malleus and incus

Question 21

Treacher-collins syndrome is disorder of what

Answer 21

• Neural crest dysfunction –> mandibular hypoplasia, facial abnormalities
• 1st pharyngeal arch problem

Question 22

Muscles for 1st pharyngeal arch?

Answer 22

• M’s and T’s
• Muscles of mastication: Masseter, Medial and lateral pterygoid, Temporalis
• Mylohyoid
• Tensor Tympani
• Tensor veli palitini
• anterior 2/3 of Tongue

Question 23

Nerve for 1st pharyngeal arch

Answer 23

M’s and T’s

-Mandibular and Maxillary branches of Trigeminal N

Question 24

Cartilage for 2nd pharyngeal Arch

Answer 24

“S”

• Stapes
• Styloid process
• Stylohyoid ligament
• lesser horn of the hyoid

Question 25

Muscles for 2nd pharyngeal arch?

Answer 25

“S”

• muscles of facial expression
• Stapedius
• Stylohyoid

Question 26

Nerve for 2nd pharyngeal arch

Answer 26

“S”

-CN Seven (facial)

Question 27

Muscle for 3rd pharyngeal arch?

Answer 27

styloPHARYNGEUS

Question 28

Nerve for 3rd pharyngeal arch

Answer 28

GlossaPHARYNGEAL

Question 29

cartilage for 3rd pharyngeal arch

Answer 29

none

Question 30

Cartilage for 4th and 6th pharyngeal arches

Answer 30

• Cricoid cartilage
• Thyroid cartilage
• cartilage of larynx

Question 31

Muscles for 4th and 6th pharyngeal arches

Answer 31

• 4th: cricothyroid M. and pharyngeal muscles (swallowing)

- 6th: rest of laryngeal muscles (speech)

Question 32

Nerves for 4th and 6th pharyngeal arches

Answer 32

“4+6=10 (Vagus)”

• Superior Laryngeal br. —> pharyngeal muscles for swallowing (4th)
• Recurrent Laryngeal branches —> Laryngeal muscles for speech (6th)