Lecture 32: Development of Head and Neck I

Question 1

What cells generally gives rise to structures in the craniofacial region?

Answer 1

Neural crest cells

Question 2

Name the early primordia for the facial region

Answer 2

Frontonasal prominence, ectodermal nasal placodes, maxillary and mandibular processes

Question 3

What is the pharyngeal arch tissue derived from mesoderm of somitomeres?

Answer 3

Musculature

Question 4

What is responsible for pharyngeal arch mesenchyme (except for musculature)?

Answer 4

Neural crest

Question 5

Expression of what group of genes is responsible for segmentation of cranial neural tube?

Answer 5

Hox genes

Question 6

What signals the prepatterning of cranial ectoderm?

Answer 6

FGF-8

Question 7

What is responsible for patterning endoderm of the first pharyngeal pouch?

Answer 7

Otx2

Question 8

What is responsible for patterning the endoderm of pharyngeal pouches 2-4?

Answer 8

Retinoic acid

Question 9

What group of genes heavily influence dorsoventral patterning of pharyngeal arches?

Answer 9

Dlx genes

Question 10

The frontonasal ectodermal zone is induced by Shh from which area?

A. Forebrain
B. Midbrain
C. Hindbrain
D. Pharyngeal arches

Answer 10

A. Forebrain

Question 11

What is the primary function of the FGF-8/Shh gradient in the frontonasal ectodermal zone?

Answer 11

Shaping of the tip of the snout

Question 12

What are the primordia of the face?

Answer 12

Frontonasal prominence, nasomedial processes, nasolateral processes

Question 13

What are the primordia for the jaws?

Answer 13

Maxillary processes, Mandibular processes, Meckel’s cartilage

Question 14

What is responsible for subdivision of the first pharyngeal arch into upper and lower jaw primordia?

Answer 14

Endothelin-1

Question 15

What are the derivatives of Meckel’s cartilage?

Answer 15

Articular and Quadrate cartilages

Question 16

What is Meckel’s cartilage derived from?

Answer 16

Neural crest

Question 17

What does the quadrate bone become in mammals?

Answer 17

Incus

Question 18

What does the articular bone become in mammals?

Answer 18

Malleus

Question 19

Expression of what gene is involved in the formation of the temporomandibular joint in mammals?

Answer 19

Barx-1

Question 20

What are the primordia for the palate?

Answer 20

Unpaired median palatine process (premaxilla), paired lateral palatine processes (secondary plate)

Question 21

Hypoplasia of the mandible and facial bones is commonly associated with an autosomal dominant condition involving the TCOF1 gene. In this condition, there is a reduced population of neural crest cells in the 1st pharyngeal arch. This condition is associated with which of the following anomalies?

A. Treacher-Collins Syndrome
B. Waardenburg Syndrome
C. Ankyloglossia
D. DiGeorge Syndrome

Answer 21

A. Treacher-Collins Syndrome

Question 22

Which of the following is derived from Rathke’s pouch?

A. Thyroid
B. Diencephalon
C. Adenohypophysis
D. Olfactory epithelium

Answer 22

C. Adenohypophysis

Question 23

The auditory tube is a derivative of which pharyngeal pouch?

Answer 23

First pharyngeal pouch