Face, Mouth Pharynx Development

Question 1

Which structures are involved in the development of the face (mouth and nasal cavity)

Answer 1

Frontonasal prominence
Medial and lateral nasal processes
Mandibular arch 1
Maxillary prominence

Question 2

Where does the face originate?

Answer 2

Neural crest cells

Question 3

How are the base bones of the skull developed?

Answer 3

Endochondral ossification

Question 4

How are the face bones developed?

Answer 4

Intramembranous ossification

Question 5

What does the medial nasal prominence and mandibular prominence form when they fuse?

Answer 5

Nasal septum and the primary pallate

Question 6

The development of the nasal and oral cavities?

Answer 6

1. Oronasal membrane separates the oral and nasal cavities
2. Breakdown of the oronasal membrane –> temporary confluence of both cavities
3. Formation of the primary palate
4. Formation of the secondary palate

Question 7

Nasolacrimal Duct

Answer 7

Lateral nasal process and maxillary prominence fusion line
Ectoderm thickens and forms ND

Question 8

What does the frontal prominence form?

Answer 8

Frontal bone
Forehead area

Question 9

What does the lateral nasal prominence form?

Answer 9

Nasal & lacrimal bones
Sides and alae of nose

Question 10

What does the medial nasal prominence form?

Answer 10

Vomer and incisive bones
Medial part of the upper lip and gingiva, nasal septum

Question 11

What does the Mandibular prominence form?

Answer 11

Mandible
Lower lip, gingiva and cheeks

Question 12

What does the maxillary prominence form?

Answer 12

Maxillae, palatine, petryoid, zygomatic and squamous parts of temporal bones
Upper lip, gingiva and cheeks

Question 13

How are salivary glands formed?

Answer 13

Epithelium: ectoderm and endoderm
CT: mesenchyme of brachial arch 1

Question 14

How is the pituitary gland formed?

Answer 14

Oral ectoderm (Rathke’s pouch) and diencephalon

Question 15

How is the 2 lateral swellings of the tongue developed?

Answer 15

Mandibular arch 1

Question 16

How is the medium tuberculum impar of the tongue developed?

Answer 16

Tubercle arch 1 &2

Question 17

How is the copula and body of the tongue developed?

Answer 17

C: Arches 3 & 4
B: Lateral and medial swelling (ectoderm)

Question 18

How is the root, muscle and CT of the tongue developed?

Answer 18

R: copula (endoderm)
M: Occipital somites
CT: brachial mesenchyme

Question 19

How is the tongue innervated?

Answer 19

Body: Arch 1= trigeminal
Root: Arches 3 & 4 = glossopharyngeal and vagus
Muscles: Hypoglossal

Question 20

How are the taste buds innervated?

Answer 20

Special sensory (from arch 2) by facial n.

Question 21

How is the enamel of the tooth developed?

Answer 21

Ectoderm –> inner enamel epithelium –> ameloblasts

Question 22

How is the dentin of the tooth developed?

Answer 22

Neural crest –> pulp cavity –> ondontoblasts

Question 23

How is the pulp cavity of the tooth developed?

Answer 23

Mesenchyme

Question 24

How is the cementum of the tooth developed?

Answer 24

Mesenchyme –> dental sac –> cementocyte

Question 25

How is periodontal and alveolar bone of the tooth developed?

Answer 25

Mesenchyme –> dental sac –> fibroblasts/ osteocytes (cementocyte)

Question 26

How is Arch 4 & 6, laryngeal and pharyngeal muscles innervated?

Answer 26

Vagus nerve

Question 27

How are mastication muscles innervated?

Answer 27

Trigeminal nerve

Question 28

What is the only muscle what glossopharyngeal nerve innervates?

Answer 28

Stylopharyngeus muscle

Question 29

What does each (6) pharyngeal arch consist of?

Answer 29

Mesenchymal core
Endoderm pouch
Ectodermal clefts

Question 30

What does cleft 1 of the pharyngeal cleft develop into?

Answer 30

Dorsal part is the external auditory meatus
Outer epithelium of the eardrum

Question 31

What happens to the rest of the pharyngeal clefts?

Answer 31

Cleft 2 mesenchyme overgrows 3 & 4 and merges with the epicardial ridge in the neck
Merge and form a cervical sinus (disappears with development)
If persists: cyst, sinus or fistula on lateral side of the neck

Question 32

What does the pharyngeal pouch 1 develop into?

Answer 32

Dorsal: auditory tube, tympanic cavity (guttural pouch)

Question 33

What does pouch 2 develop into?

Answer 33

Dorsal: Crypt of palatine tonsil
Ventral: none

Question 34

What does pouch 3 develop into?

Answer 34

Dorsal: External parathyroid
Ventral: reticular cells of thymus

Question 35

What does pouch 4 develop into?

Answer 35

Dorsal: internal parathyroid (non in pig)

Question 36

How does the thyroid gland develop?

Answer 36

From endoderm of the floor of the pharynx between pouch 1 & 2 –> then goes to first 2 tracheal ring

Question 37

Cleft lip

Answer 37

Rare in domestic animals
Lack of fusion of medial nasal prominences with each other or with maxillary prominences

Question 38

Which animals is cleft lip normal in?

Answer 38

Sheep
intermediate in dogs

Question 39

Cleft palate?

Answer 39

Defect in the incisive bone due to the failure of medial nasal prominences to fuse
Failure of palatine processes of maxilla to fuse

Question 40

Facial cleft

Answer 40

Extends for the nasal cavity to medial canthus of the eye
Caused by failure of maxillary prominence to fuse with lateral nasal prominence

Question 41

Atresia of the nasolacrimal duct

Answer 41

Failure of epithelial cells between maxillary and lateral nasal prominences to canalize
Results in overflow of lacrimal glands secretion

Question 42

Agnathia (absent) and bracnygnathia (subnormal) inferior or superior

Answer 42

Mal-development of lower of upper jaw, respectively