Development of the Head and Neck pt. 1

Question 1

Manyt head and neck structures form from the mesoderm-mesenchyme found in and near five bilateral pairs of

Answer 1

Pharyngeal (branchial) Arches

Question 2

These 5 pharyngeal arches appear during the

Answer 2

Fourth week of prenatal development

Question 3

The five pharyngeal arches appear during the 4th week of prenatal development and are numbered

Answer 3

1, 2, 3, 4, and 6 (the 5th quickly disappears)

Question 4

Precursor cells in pharyngeal arches and in regions rostral to pharyngeal arches are derived from

Answer 4

Mesoderm and Neural crest

Question 5

Each pharyngeal arch is a bar of mesoderm-mesenchyme that is separated by

Answer 5

Folds of surface ectoderm (pharyngeal clefts/grooves) and folds of endoderm (pharyngeal pouches)

Question 6

Contains its own specific nerve, artery, muscle, and connective tissure

Answer 6

Ech pharyngeal arch

Question 7

Cranial nerves extend from the developing brainstem into

Answer 7

Pharyngeal arches

Question 8

Conversely, pharyngeal arch mesoderm and neural crest gives rise to

Answer 8

Aortic arches, skeletal muscles, and connective tissues

Question 9

Pharyngeal arch 1 is comprised of which two prominences?

Answer 9

Maxillary prominence and mandibular prominence

Question 10

What is the cranial nerve that is associated with the 1st pharyngeal arch?

Answer 10

Trigeminal nerve

Question 11

What is the aortic arch of the 1st pharyngeal arch?

Answer 11

I (maxillary)

Question 12

From the mesoderm, the mandibular prominence of the 1st pharyngeal arch has which skeletal muscles?

Answer 12

Mastication muscles, tensors, anterior digastric, mylohyoid

Question 13

The maxilla, zygomatic bone, squamous temporal bone, palatine, and volmer are the connective tissues (derived from neural crest) associated with the

Answer 13

Maxillary prominence of 1st pharyngeal arch

Question 14

What is the nerual crest connective tissue associated with the mandibular prominance of the 1st pharyngeal arch?

Answer 14

Mandible, malleus, and incus

Question 15

What is the cranial nerve of the second pharyngeal arch?

Answer 15

Facial nerve (VII)

Question 16

What is the aortic arch of the 2nd pharyngeal arch?

Answer 16

II (stapedial)

Question 17

What are the mesodermal skeletal muscles of the 2nd pharyngeal arch?

Answer 17

Facial expression muscles, stapedius, posterior digastric, and stylohyoid

Question 18

The stapes, styloid process, lesser hgorn of hyoid bone, and upper body are neural crest connective tissues of the

Answer 18

2nd pharyngeal arch

Question 19

What is the cranial nerve of the 3rd pharyngeal arch?

Answer 19

Glossopharyngeal nerve (IX)

Question 20

What is the aortic arch of the 3rd pharyngeal arch?

Answer 20

III (part of internal carotid)

Question 21

What is the mesodermal skeletal muscle of the 3rd pharyngeal arch?

Answer 21

Stylopharyngeus

Question 22

What are the neural crest derived connective tissues of the 3rd pharyngeal arch?

Answer 22

Greater hgorn of hyoid and lower body

Question 23

What is the cranial nerve of the 4th pharyngeal arch?

Answer 23

X (Superior lingual of vagus)

Question 24

What is the aortic arch of the 4th pharyngeal arch?

Answer 24

IV (parts of right subclavian and aortic arch)

Question 25

The soft palate muscles (except tensor) and the pharyngeal muscles (except stylopharyngeus and cricothyroid) are the mesodermal skeletal muscles of the

Answer 25

4th pharyngeal arch

Question 26

What is the neural crest derived connective tissue of the 4th pharyngeal arch?

Answer 26

Laryngeal cartilage

Question 27

What is the cranial nerve of the 6th pharyngeal arch?

Answer 27

X (recurrent laryngeal nerve of vagus)

Question 28

What is the aortic arch of the 6th pharyngeal arch?

Answer 28

VI (Ductus arteriosis and pulmonary)

Question 29

What are the mesodermal skeletal muscles of the 6th pharyngeal arch?

Answer 29

Intrinsic laryngeal (except cricothyroid) and esophageal muscles

Question 30

What are the neural crest derived connective tissues of the 6th pharyngeal arch?

Answer 30

Laryngeal cartilage

Question 31

The stomodeum (primitive mouth) and pharynx meet at the oropharyngeal/buccopharyngeal membrane where the

Answer 31

Ectoderm meets endoderm without intervenin mesoderm

Question 32

The oropharyngeal membrane disintegrates, which allows for a continuouslumen between the 1. ) Ectoderm lined? 2. ) Endoderm lined?

Answer 32

1.) Stomodeum (primitive mouth) 2.) Foregut

Question 33

Derived from multiple pharyngeal arches and extends from the pharynx into the stomodeum

Answer 33

Tongue

Question 34

The epithelium covering the anterior 2/3 of the tongue and the surrounding oral cavity are derived from

Answer 34

Ectoderm

Question 35

The glandular epithelium of the parotid gland is derived from

Answer 35

Ectoderm

Question 36

The epithelium covering the pharyngeal part fo the tongue (posterior 1/3) and surrounding oropharynx are derived from?

Answer 36

Endoderm

Question 37

The glandular epithelium of the submandibular and sublingual glands is derived from

Answer 37

Endoderm

Question 38

However, the supportive glandular stroma is derived from

Answer 38

Mesoderm-mesenchyme of associated arches

Question 39

For the posterior 1/3 of the tongue, the general sensory and taste information is conveyed through the

Answer 39

Glossopharyngeal nerve (IX)

Question 40

It should be noted that some taste information in the posterior 1/3 of the tongue is also provided by the

Answer 40

Vagus nerve

Question 41

The somatic MOTOR innervation to all skeletal muscles of the tongue (except the palatoglossus) is conveyed through the

Answer 41

Hypoglossal Nerve (XII)

Question 42

The Palatoglossus is innervated by the

Answer 42

Vagus nerve (X)

Question 43

Proliferates in the midline of the ventral wall of the pharynx to form the connective tissue that contains sensory nerves of the anterior 2/3 and posterior 1/3 of the tongue

Answer 43

Tongue pharyngeal arch mesenchyme

Question 44

Tongue skeletal muscle forms from migrating myoblasts of

Answer 44

Occipital somitomeres

Question 45

Forms from the growth of the two lateral lingual swellings and a median lingual sweeling (tuberculum impar) in the 1st pharyngeal arch

Answer 45

The anterior 2/3 of the tongue

Question 46

Make up most of this growth and meet in the midline of the tongue as the median lingual sulcus

Answer 46

Lateral lingual swellings

Question 47

The lateral lingual swellings make up most of the growth of the anterior 2/3 of the tongue and meet in the midline as the

Answer 47

Median lingual sulcus

Question 48

Failure of the lateral lingual swellings to completely fuse in the midline results in

Answer 48

Bifid tongue

Question 49

Forms from the hypopharyngeal eminence in the 3rd and 4rth pharyngeal arches

Answer 49

Posterior 1/3 of the tongue

Question 50

Defines the boundary between the anterior and posterior tongue

Answer 50

Terminal sulcus

Question 51

The location of midline ventral endodermal envagination to form the thyroid gland -at the root of the tongue

Answer 51

Foramen cecum (Thyroid diverticulum)

Question 52

Myoblasts from occipital somitomeres migrate to the developing tongue mesenchyme and drag the -for somatic innervation

Answer 52

Hypoglossal nerve

Question 53

The face and palate formation begins anteriorly as 5 mesenchymal prominences (bumps) at about

Answer 53

4-5 weeks

Question 54

These mesenchymal prominences (bumps) surround the stomodeum and are covered by

Answer 54

Surface ectoderm

Question 55

Derived from the mesenchyme rostral to the pharyngeal arches and lies ventral to the forebrain and cranial stomodeum

Answer 55

The single midline Frontonasal prominence

Question 56

The single midline frontonasal prominence lies 1. ) Ventral to the 2. ) Cranial to the

Answer 56

1. ) forebrain 2. ) stomodeum

Question 57

The pair of maxillary prominences of the first pharyngeal arch lie LATERAL to the

Answer 57

Stomodeum

Question 58

The pair of mandibular prominences of the first pharyngeal arch lie CAUDAL to the

Answer 58

Stomodeum

Question 59

These prominences contain connective tissue-forming mesenchymal cells covered by

Answer 59

Epidermis-forming surface ectoderm

Question 60

As these prominences proliferate and migrate towards the midline, they form the

Answer 60

Face and palate

Question 61

Deformities of the lip and palate are described as anterior and/or posterior to the incisive foramen and may be

Answer 61

Unilateral or bilateral

Question 62

Bilateral surface ectoderm thickenings that develop on the frontonasal prominence

Answer 62

Nasal placodes

Question 63

Lateral and medial prominences surround each nasal placode and grow forward while the placodes remain stationary. This gives the impression of "invaginations" to form

Answer 63

Nasal cavities

Question 64

This nasal placode ectoderm will form the epithelium lining of nasal cavities, including the olfactory epithelium that is responsible for the sense of

Answer 64

Smell

Question 65

More specifically, surface-ectoderm nasal placodes form "pits" that become

Answer 65

Nasal cavities lined by nasal epithelium

Question 66

Frontonasal prominence mesenchyme develop as "rises" that will form

Answer 66

Midline structures (nose, philtrum of upper lip, primary palate)

Question 67

The "rises" surrounding the "pits" are called

Answer 67

Medial and lateral nasal prominences

Question 68

Fusion of themedial nasal prominences creates the intermaxillary segment that develops into the

Answer 68

Primary palate (anterior to incisive foramen)

Question 69

Proliferation of the adjacent maxillary prominences "pushes" the midline fusion of the medial nasal prominences to form the

Answer 69

Intermaxillary segment

Question 70

The frontonasal prominence also gives rise to

Answer 70

Forehead and nasal septum