Embryology Of The Head, Face & Oral Cavity

Question 1

Embryology

Answer 1

Study of the development of tissues

Question 2

Oral embryology

Answer 2

The study of development of oral tissues

Question 3

Embryogenesis

Answer 3

Process of embryological development, forming of tissues and organs.

Question 4

Embryonic origins

Answer 4

3 tissue layers of tri-laminar embryonic disk that give rise to all tissues in the body.
(Ectoderm
Mesoderm
Endoderm)

Question 5

Derivatives

Answer 5

Structures that the origins/tissue layers form

Question 6

3 embryonic origins

Answer 6

Ectoderm
Mesoderm
Endoderm

Question 7

3 key phases of embryogenesis and development

Answer 7

Early embryogenesis (weeks 1-4)
Embryogenesis (weeks 5-8)
Fetal development (week 9-birth)

Question 8

Where does the connective tissue in head, face and oral cavity derivatate from

Answer 8

Ectoderm - neuroectoderm - neural crest cells - ectomesenchyme

Question 9

Key stages of early embryogenesis

Answer 9

Fertilisation
Cleavage
Proliferation
Migration
Differentiation

Question 10

What forms in 2-3 weeks of early embryogenesis, when the embryoblast within the blastocyst proliferations and changes

Answer 10

Blaminar embryonic disc
Ectoderm
Endoderm

Question 11

Trophoblast

Answer 11

Cell lining the blastocyst

Question 12

Blastocoel

Answer 12

Primary fluid filled space within blastocyst

Question 13

Embryoblast

Answer 13

Cluster of cells within blastocyst

Question 14

What does the bilaminar embryonic disc change into as it grows

Answer 14

Trilaminar embryonic disc
Ectoderm - outside
Mesoderm - middle
Endoderm - inside

Question 15

What do the fold form in week 4 of early embryogenesis

Answer 15

Embryo starts to take shape through folds forming:
Stomodeum (primitive mouth)
Bucco-pharyngeal membrane
Primitive gut

Question 16

Building blocks to the structures of the face and oral cavity

Answer 16

Pharyngeal arches (branchial arches)

Question 17

When do the pharyngeal arches devleop

Answer 17

Week 4 early embryogenesis

Question 18

1st pharyngeal arch
Nerve and muscles

Answer 18

Trigeminal nerve
Muscles of mastication

Question 19

2nd pharyngeal arch
Nerves and muscles

Answer 19

Facial nerve
Muscles of facial expression

Question 20

3rd pharyngeal arch
Nerves and muscles

Answer 20

Glossopharyngeal nerve
Stylopharyngeal muscle (swallowing)

Question 21

4th pharyngeal arch
Nerves and muscles

Answer 21

Superior branch of vagus nerve
Laryngeal muscles

Question 22

When does the development of head, face and oral cavity cavity occur

Answer 22

Embryogenesis weeks 5-8

Question 23

Prominences that fuse together to form the face

Answer 23

1x frontonssal prominence
2x maxillary prominence
2x mandibular prominence
Embryogenesis weeks 4-6

Question 24

When does the development of the primary palate occur and how

Answer 24

Weeks 6-7 embryogenesis
Frontonasal prominence and medial nasal prominences fuse together.

Question 25

When does the development of the secondary palate occur and how

Answer 25

Weeks 7-8 embryogenesis.
After primary palate.
Palatine shelves grow from either side and fuse at midline and with primary palate and nasal septum.
Incisive foramen forms.

Question 26

When does the development of the tongue occur and how

Answer 26

Week 4-7 embryogenesis.
1st, 2nd and 4th pharyngeal arches.

Question 27

Development of anterior 2/3rds of tongue

Answer 27

Form from
2x lateral lingual swellings 1st pharyngeal arch.
Tuberculum impar 2nd pharyngeal arch.

Question 28

Development of posterior 1/3rd of tongue

Answer 28

Forms form
Copula eminence 4th pharyngeal arch.

Question 29

What has to occur to allow the tongue to separate from floor of mouth

Answer 29

Cellular apoptosis
Leaves frenum behind as anchor

Question 30

When and how does the development of the alveolar bone occur

Answer 30

Week 7 embryogenesis
Maxilla and mandible jaws undergo ossification starting from maxilla and mandibular prominences.

Question 31

What does each jaw develop

Answer 31

Neural and alveolar portion - Support the development of teeth.

Secondary cartilages - Support growth of bone throughout life.

Question 32

Where do the skull bones derive from

Answer 32

Neural crest cells and mesoderm

Question 33

3 sections of skull development

Answer 33

Cranial vault (brain case)
Cranial bones
Facial bones

Question 34

At what age do the cranial bones fully fuse and why?

Answer 34

6-7 years old
Allow for brain growth and development

Question 35

When does the fetal development phase occur

Answer 35

After the first 8 weeks
Week 9 - birth

Question 36

What is the focus of fetal development

Answer 36

Growth of fetus.
Continuation of development and maturation of structures that have formed.

Question 37

Aetiology of anomalies in embryology

Answer 37

• Genetic
• Environmental/congenital (infections, radiation, hormones, nutritional deficiencies, medications)

Question 38

What type of abnormality is cleft lip and/or palate

Answer 38

Congenital anomalies.
Happens due to local cause or disruption in process.

Question 39

How common is cleft lip palate

Answer 39

1 in 700 live births

Question 40

Cleft lip

Answer 40

Failure of fusion of 2 medial nasal processes
and/or
Maxillary and mesial nasal processes.
Unilateral or bilateral.

Question 41

Cleft palate

Answer 41

Failure of fusion of palatine shelves together
and/or
the nasal septum.

Question 42

What do cleft lip and palate patients remain at higher risk for

Answer 42

Oral disease.
Impact on development of teeth.