PPT 5: Embryological Development

Question 1

Neurocranium (Vault, Cranial Base) or Viscerocranium?
A. Nasal, Mandible bones
B. Hyoid, middle ear bones
C. Ethmoid, petrous temporal bones
D. Parietal, frontal bones

Answer 1

A. Viscero
B. Viscero
C. Neuro - cranial base
D. Neuro - vault

Question 2

Endochondrial or Intramembranous ossification?
A. Vault bones
B. Cranial base bones 
C. Cartilaginous bones: ossicles, hyoid
D. Face bones

Answer 2

A. Intramembranous
B. Endochondrial
C. Endochondrial
D. Intramembranous

Question 3

Longitudinal or lateral growth?
A. Spheno-occipital joint
B. Temporal and sphenoid bones
C. Ends in mid teens
E. Involves synchodrosis joint

Answer 3

A. Longitudinal growth
B. Lateral growth.
C. Longitudinal growth. S-E and S-O joints close.
D. Both

Question 4

What is the cranial base angle and how does it affect the shape of the face?

Answer 4

Angle between occiput and sphenoid.
Large angle = overbite
Small angle = underbite

Question 5

What types of cells converge in the pharyngeal arches? What types of tissues do these cells produce?

Answer 5

Mesenchyme and neural crest cells converge to form pharyngeal arches. These cells form bones, cartilage, skin, arteries, and nerves of the face.

Question 6

Name the Pharyngeal Arch: 1 (mandibular), 2 (hyoid), 3, 4
A. Glossopharyngeal CN IX
B. Trigeminal CN V
C. Vagus CN X
D. Facial CN VII

Answer 6

A. 3
B. 1
C. 4
D. 2

Question 7

Name the Pharyngeal Arch: 1 (mandibular), 2 (hyoid), 3, 4
A. Mandible, maxilla
B. Hyoid
C. Larynx
D. Styloid process

Answer 7

A. 1
B. 2 and 3
C. 4
D. 2

Question 8

Name the Pharyngeal Arch: 1 (mandibular), 2 (hyoid), 3, 4
A. Stapes
B. Malleus, Incus
C. Zygoma
D. Squamous Temporal

Answer 8

A. 2
B. 1
C. 1
D. 1

Question 9

What does the pharyngeal groove become? What does pouch 1 become?

Answer 9

Groove = External acoustic meatus (ear canal)

Pouch 1 = Tympanic cavity, Eustacian/auditory tube

Question 10

Which pharyngeal pouch? 1, 2, 3, or 4?
A. Parathyroid and C cells of thyroid
B. Thymus and parathyroid
C. Palatine tonsil
D. Structures migrate down into neck from

Answer 10

A. 4
B. 3
C. 2
D. 3 and 4

Question 11

Cleft lip is caused by incomplete or complete failure of fusion of _______.

Answer 11

Maxillary and medial nasal prominences

Question 12

What two failures of fusion can result in a cleft palate?

Answer 12

(1) the palatine processes (shelves) fail to fuse at midline

(2) the fusion between primary and secondary palates does not occur

Question 13

T or F? Skull bones and cartilage are formed from:
A. Neural crest cells
B. Local mesoderm somites
C. Lateral plate mesoderm
D. Outer epithelial layers

Answer 13

A, B, and D are true

Question 14

T or F?
The eventual shape of the skull is determined by the development of the vault bones in relation to intermembranous growth centers.

Answer 14

False. It is determined by the soft tissues (brain, connective tissues, and muscles)

Question 15

What is a synchodrosis joint?

Answer 15

It is a temporary form of joint where the cartilage is converted into bone before adult life (epiphyseal growth plate) (from Wikipedia)

Question 16

Name the Pharyngeal Arch: 1 (mandibular), 2 (hyoid), 3, 4
A. Tensors tympani and palati m
B. Facial expression, posterior diagastric m
C. All facial development comes from this arch
D. Masticators, anterior diagastric m

Answer 16

A. 1
B. 2
C. 1
D. 1

Question 17

Name the Pharyngeal Arch: 1 (mandibular), 2 (hyoid), 3, 4
A. Stapedius m
B. Muscles of pharynx and larynx
C. Stylohyoid m
D. Stylopharyngeus m

Answer 17

A. 2
B. 4
C. 2
D. 3

Question 18

Thyroid descends from base of tongue through _______ and ________, anterior of hyoid bone and larynx.

Answer 18

Foramen cecum and thyroglossal duct