Embryology of the Head & Neck

Question 1

Stomodeum gives rise to the ____.

Answer 1

mouth

Question 2

Frontal nasal prominence gives rise to the ____.

Answer 2

nose

Question 3

How many pairs of pharyngeal arches form?

Answer 3

5

Question 4

1st pharyngeal arch has 2 sub units: ____ and ____.

Answer 4

maxillary and mandibular prominences

Question 5

Formation of pharyngeal arches is driven by proliferation and migration of ____.

Answer 5

neural crest cells

Question 6

Pharyngeal arches are covered by ____. lined by ____, with a core made up of ____.

Answer 6

ectoderm, endoderm, mesenchyme

Question 7

1st pharyngeal arch is innervated by ____.

Answer 7

CN V - Trigeminal

Question 8

2nd pharyngeal arch is innervated by ____.

Answer 8

CN VII - Facial

Question 9

3rd pharyngeal arch is innervated by ____.

Answer 9

CN IX - Glossopharyngeal

Question 10

4th & 6th pharyngeal arches are innervated by ____.

Answer 10

CN X - Vagus

Question 11

The 1st pharyngeal arch differs from the others, in that it is lined predominantly by ____.

Answer 11

ectoderm

Question 12

Pharyngeal ____ separate the arches from the outside.

Answer 12

grooves

Question 13

Pharyngeal ____ separate the arches from the inside.

Answer 13

pouches

Question 14

The ____ is where the ectoderm and endoderm come together at the grooves/pouches.

Answer 14

pharyngeal membrane

Question 15

neural crest derivatives of arch 1 - maxillary prominence

Answer 15

facial bones (maxillary, zygomatic, squamous portion of temporal)

Question 16

neural crest derivatives of arch 1 - mandibular prominence

Answer 16

Meckel’s Cartilage - mandible, inner ear bones (incus & malleus), anterior ligament of malleus

Question 17

neural crest derivatives of arch 2

Answer 17

Reichart Cartilage - lesser cornu of hyoid (superior), stylohyoid ligament, styloid process, stapes

Question 18

neural crest derivatives of arch 3

Answer 18

body & greater cornu of hyoid (inferior)

Question 19

neural crest derivatives of arch 4/6

Answer 19

thyroid & cricoid cartilage

Question 20

mesoderm derivatives of arch 1

Answer 20

muscles of mastication (temporalis, masseter, mylohyoid, ant. digastric, tensor tympani)

Question 21

mesoderm derivatives of arch 2

Answer 21

muscles of facial expression (buccinator, orbicularis oris, frontalis, etc), stylohyoid, & post. digastric

Question 22

mesoderm derivatives of arch 3

Answer 22

stylopharyngeus

Question 23

mesoderm derivatives of arch 4/6

Answer 23

pharyngeal constrictors, m. of soft palate, & m. of larynx

Question 24

sensory innervation of arch 1

Answer 24

CN V - somatosensation of face, teeth, palate, and ant. 2/3 of tongue

Question 25

sensory innervation of arch 2

Answer 25

CN VII - taste to ant. 2/3 of tongue

Question 26

sensory innervation of arch 3

Answer 26

CN IX - taste and somatosensory to post. 1/3 of tongue

Question 27

sensory innervation of arch 4/6

Answer 27

CN X - taste and somatosensory to pharynx, larynx & esophagus

Question 28

endoderm derivative of pharyngeal pouch 1

Answer 28

middle ear cavity & auditory tube

Question 29

endoderm derivative of pharyngeal pouch 2

Answer 29

palatine tonsils

Question 30

endoderm derivative of pharyngeal pouch 3

Answer 30

inferior parathyroid glands & thymus

Question 31

endoderm derivative of pharyngeal pouch 4/6

Answer 31

superior parathyroid glands & ultimopharyngeal bodies

Question 32

derivative of pharyngeal groove 1

Answer 32

external auditory meatus

Question 33

derivative of pharyngeal grooves 2-4

Answer 33

cervical vesicle, which eventually degrades

Question 34

Cervical cyst/fistula/sinus occurs due to incomplete degradation of the ____.

Answer 34

cervical vesicle

Question 35

The ____ forms as a diverticulum in the endoderm between pharyngeal arch 1 & 2.

Answer 35

thyroid primordium

Question 36

The ____ connects the thyroid primordium with the ____ and eventually opens into the tongue via the ____.

Answer 36

thyroglossal duct, pharynx, foramen cecum

Question 37

The thyroglossal duct typically ____, but in rare cases remains and forms the ____ of the thyroid.

Answer 37

degrades, pyramidal lobe

Question 38

A ____ occurs when the thyroglossal duct improperly or incompletely degrades. Sometimes it contains ectopic thyroid tissue.

Answer 38

thyroglossal duct cyst

Question 39

The development of the tongue involves pharyngeal arches ____ to ____.

Answer 39

1 to 4

Question 40

The ____ develops in the first pharyngeal arch as the beginning of the development of the tongue.

Answer 40

median lingual swelling

Question 41

The median lingual swelling plays an inductive role in the formation of the ____.

Answer 41

lateral lingual swelling

Question 42

The lateral lingual swelling gives rise to the ____.

Answer 42

anterior 2/3 of the tongue

Question 43

In tongue formation, the 2nd pharyngeal arch gives rise to the ____ which eventually degrades, but plays an inductive role in the formation of the ____ from arches 3 & 4.

Answer 43

copula, hypopharyngeal eminence

Question 44

In tongue formation, the 2nd pharyngeal arch also gives rise to the ____.

Answer 44

taste buds

Question 45

The hypopharyngeal eminence from pharyngeal arches 3 & 4 gives rise to the ____.

Answer 45

posterior 1/3 of the tongue

Question 46

The median sulcus of the tongue is a remnant of ____.

Answer 46

the fusion of the lingual swellings

Question 47

The terminal sulcus of the tongue is a remnant of ____.

Answer 47

the fusion between pharyngeal arch 1 and the hypopharyngeal eminence

Question 48

The skeletal muscles of the tongue develop from ____, around week 5 of development.

Answer 48

occipital somites

Question 49

The anterior 2/3 of the tongue gets somatosensory innervation from ____ and special sensory (taste) innervation from ____.

Answer 49

CN V(3), CN VII

Question 50

The posterior 1/3 of the tongue gets somatosensory innervation from ____ and ____ and special sensory (taste) innervation from ____.

Answer 50

CN IX and X, CN IX

Question 51

The muscles of the tongue get motor innervation from ____.

Answer 51

CN XII

Question 52

What are the 4 types of papillae on the tongue?

Answer 52

filiform, fungiform, folliate, and circumvallate

Question 53

Which papillae of the tongue contain taste buds?

Answer 53

fungiform, folliate, and circumvallate

Question 54

Taste buds relay special sensory (taste) information via ____ and ____.

Answer 54

CN VII and IX

Question 55

Formation of the face begins as how many facial primordia around the stomodeum?

Answer 55

5

Question 56

What are the 5 facial primordia?

Answer 56

Frontonasal Prominence (FNP), Paired Maxillary Prominences (MxP), and Paired Mandibular Prominences (MdP)

Question 57

An ectodermal thickening, called the ____, forms on the FNP.

Answer 57

nasal placodes

Question 58

The mesenchyme below the nasal placodes proliferates and elevates up around the nasal placodes to form the ____.

Answer 58

nasal prominences

Question 59

The nasal placode invaginates into the underlying mesenchyme to form the ____ and dilates to become the ____.

Answer 59

nasal pit, nasal sac

Question 60

Growth and enlargement of the ____ push the nasal prominences to the midline, forcing them to fuse.

Answer 60

maxillary prominences

Question 61

Midline fusion of the nasal prominences gives rise to the ____ and ____.

Answer 61

bridge of the nose, intermaxillary segment

Question 62

The intermaxillary segment gives rise to the ____, ____, and ____.

Answer 62

philtrum (of upper lip), upper jaw w/ 4 incisors, primary palate

Question 63

The intermaxillary segment fuses with the ____ to allow fusion of the ____ and ____.

Answer 63

maxillary prominences, upper lip, palate

Question 64

____ also fuse with the maxillary prominence, and incomplete fusion results in ____.

Answer 64

lateral nasal prominences, oblique cleft

Question 65

____ forms at the site of fusion between the MxP and lateral nasal prominences, due to thickening and invagination of the ectoderm.

Answer 65

nasolacrimal duct

Question 66

The two ____ fuse at the midline to form a single nasal cavity.

Answer 66

nasal pits

Question 67

During development, the oral and nasal cavities are continuous due to the rupture of the ____.

Answer 67

oronasal membrane

Question 68

Formation of the ____ ultimately separates the oral and nasal cavities.

Answer 68

secondary palate

Question 69

____ develop from the lateral walls of the nasal cavity.

Answer 69

nasal conchae

Question 70

Cranial ectoderm in the nasal cavity differentiates to become the specialized ____.

Answer 70

olfactory epithelium

Question 71

The primary palate is derived from the ____.

Answer 71

intermaxillary segment

Question 72

The secondary palate is derived from the fusion of the ____.

Answer 72

palatine shelves

Question 73

The palatine shelves grow from the ____.

Answer 73

maxillary prominence

Question 74

At about week 9, the growing mandible allows the tongue to drop down, leaving room for the ____ to fuse at the midline, and to fuse anteriorly with the ____.

Answer 74

palatine shelves, primary palate

Question 75

Improper fusion of palatine shelves or of primary and secondary palate can result in ____.

Answer 75

cleft palate

Question 76

____ is an autosomal dominant gene mutation in a protein involved in preribosomal processing. Symptoms include cleft palate, micronathia, conductive deafness, and deformed facial features. Results from neural crest defects in pharyngeal arches ___ and ___.

Answer 76

Treacher Collins Syndrome, 1 and 2

Question 77

____ is characterized by micronathia, cleft palate, and susceptibility to respiratory distress syndrome at birth. It presents with heterogeneous birth defects with a range of severity.

Answer 77

Pierre Robin Syndrome

Question 78

____ is caused by a ~30 gene deletion on chromosome 22. It presents with a wide range of complications and severity, and is due to neural crest defects in pharyngeal arches & pouches ___, ___, ___, and ___.

Answer 78

DiGeorge Syndrome, 1, 2, 3, 4

Question 79

____ is the ectodermal origin of the teeth that develops in the mandible and maxilla.

Answer 79

dental lamina

Question 80

Dental lamina invaginates to form ____, which invaginate into themselves to form a cap around the condensing ____.

Answer 80

dental buds, dental papilla

Question 81

The dental papilla is mesenchyme derived from ____.

Answer 81

neural crest cells

Question 82

Each jaw (upper and lower) develops how many dental buds?

Answer 82

10

Question 83

The dental papilla (mesenchyme) differentiate into ____, which give rise to ____.

Answer 83

odontoblasts, dentin

Question 84

The outer epithelial/ectodermal dental cells differentiate into ____, which give rise to ____.

Answer 84

amelobasts, enamel

Question 85

Both ____ and ____ teeth are generated during fetal development, but their developmental stages are staggered.

Answer 85

deciduous, adult