Face, Development, and Pharyngeal Arches

Question 1

What cell type are the cartilage elements of pharyngeal arches 1,2, and 3 made of?

Answer 1

Neural crest cells of the mid and hind brain

Question 2

What cell type are the cartilage elements of pharyngeal arches 4 and 6 made of?

Answer 2

Lateral plate mesoderm

Question 3

All bones that are derived from pharyngeal cartilages are formed by___________.

Answer 3

Endochondral formation

Question 4

What are the names of the cartilages that are derived from the 1st pharyngeal arche?

Answer 4

-meckel’s cartilage

Question 5

What cartillage arises from the mandibular swelling?

Answer 5

Meckel’s cartilage

Question 6

What is the name of the cartilage of the second arche?

Answer 6

Reichert’s cartilage

Question 7

The laryngeal cartilages are derived from which pharyngeal arch(es)?

Answer 7

Arches 4 and 6

Question 8

The laryngeal cartilages consists of which 5 cartilages?

Answer 8

• *-thyroid cartilage
• cricoid cartilage**
• arytenoid cartilage
• corniculate cartilage
• cuneiform cartilage

Question 9

What cell type are the laryngeal cartilages of arches 4 and 6 derived from?

Answer 9

Lateral plate mesoderm

Question 10

What bones arise from the first pharyngeal arche?

Answer 10

• incus
• malleus
• Alisphenoid
• premaxilla
• maxilla
• zygomatic bone
• Squamous part of temporal bone

Question 11

Which bones are derived from meckel’s cartilage?

Answer 11

Incus and malleus

Question 12

What bones arise from the second pharyngeal arche?

Answer 12

• stapes
• lesser horn of the hyoid bone
• upper portion of the body of the hyoid bone

Question 13

What bones arise from the 3rd pharyngeal arche?

Answer 13

• lower portion of body of the hyoid bone
• greater horn of the hyoid bone

Question 14

What bones arise from the 4 and 6th pharyngeal arche?

Answer 14

None
TRICK QUESTION

Question 15

What are the rest of the facial bones formed from and how are they formed?

Answer 15

• neural crest cells
• intramembranous ossification

Question 16

The anterior ligament of the malleus and the sphenomandibular ligament are derived from which arche?

Answer 16

Arch 1

Question 17

The stylohyoid ligament is derived from which arche?

Answer 17

Arch 2

Question 18

What nerve innervates the 1st pharyngeal arche?

Answer 18

CNV- Trigeminal N. (maxillary and mandibular division)

Question 19

What nerve innervates the 2nd pharyngeal arche?

Answer 19

CNVII-facial N.

Question 20

What nerve innervates the 3rd pharyngeal arche?

Answer 20

CNIX- Glossopharyngeal nerve

Question 21

What nerve innervates the 4th and 6th pharyngeal arche?

Answer 21

CNX-Vagus N/ CN XI-Accessory n.

Question 22

What tissue are the muscles of the pharyngeal arches mainly derived from?

Answer 22

Paraxial mesoderm derived from cranial somitomere and occipital somites

Question 23

What muscles are derived from the first pharyngeal arche?

Answer 23

• Muscles of mastication
• mylohyoid mm.
• anterior belly of the digastric mm.
• tensor tympani mm.
• tensor veil palatini mm.

Question 24

The muscles that are derived from the 1st pharyngeal arche come from which cranial somitomere?

Answer 24

4th cranial somitomere

Question 25

What muscles are derived from the 2nd pharyngeal arche?

Answer 25

- muscles of facial expression - posterior belly of the digastric mm. - stylohyoid mm. - stapedius mm.

Question 26

The muscles that are derived from the 2nd pharyngeal arche come from which cranial somitomere?

Answer 26

6th cranial sometomere

Question 27

What muscles are derived from the 3rd pharyngeal arche?

Answer 27

-stylopharyngeus mm.

Question 28

The muscles that are derived from the 3rd pharyngeal arche come from which cranial somitomere?

Answer 28

7th somitomere

Question 29

What muscles are derived from the 4th pharyngeal arche?

Answer 29

- cricothyroid mm - Cricopharyngeus m.

Question 30

The muscles that are derived from the 4th pharyngeal arche come from which occipital somites?

Answer 30

Occipital somites 2-4

Question 31

What muscles are derived from the 6th pharyngeal arche?

Answer 31

- Laryngeal muscles (**except** cricothyroid- 4 arch) - Skeletal muscles of esophagus

Question 32

What tissue covers the exterior of the pharyngeal arches?

Answer 32

Ectodermal epithelium

Question 33

What tissue is found within the pharyngeal arches?

Answer 33

Mesenchymal tissue

Question 34

What tissue is found on the interior surface of the pharyngeal arches?

Answer 34

Endodermal epithelium

Question 35

How many clefts are there in the embryo at week 5?

Answer 35

4 clefts

Question 36

What happens to the first cleft during development?

Answer 36

-it moves towards the first pharyngeal pouch and becomes the external auditory meatus

Question 37

What happens to the last three clefts during development?

Answer 37

- the 2nd cleft grows and then overlaps the 3rd and 4th cleft - they form a cavity lined with ectodermal epithelium - it holds the cervical sinus

Question 38

How many pouches are seen in an embryo?

Answer 38

5 pouches

Question 39

What happens to the 1st pouch during development?

Answer 39

-it joins the first cleft to form the external auditory meatus

Question 40

What happens to the 2nd pouch during development?

Answer 40

- becomes obliterated - what's left of its epithelial lining will form buds with the surrounding mesenchyme - these will become the palatine tonsils

Question 41

What happens to the 3rd pouch during development?

Answer 41

- it will become the parathyroid glands and the thymus

Question 42

What happens to the 4th pouch during development?

Answer 42

What happens to the 4th pouch during development?

Question 43

What happens to the 5th pouch during development?

Answer 43

It will become the ultimobranchial body

Question 44

T/F: There can be cervical cysts and fistulas formation within the 2nd, 3rd and 4th clefts as development progresses

Answer 44

True

Question 45

What are the steps of the development of the thyroid gland?

Answer 45

-develops as an epithelial proliferation in the floor of the pharyngeal gut between the tuberculin impar and the copula(foramen cecum) -this then forms a downgrowth known as the thyroid diverticula -As the thyroid migrates it descends to different levels: . Anterior to hyoid bone . Anterior to trachea

Question 46

How does the thyroid gland descend to its final position?

Answer 46

-descends through the thyroglossal canal

Question 47

What tissue is the thyroid gland made from?

Answer 47

Endodermal lining of the pharynx

Question 48

T/F: A cyst can develope within the thyroglossal duct that the thyroid gland used to descend to its normal position

Answer 48

True

Question 49

How is the anterior 2/3rd of the tongue formed?

Answer 49

-proliferation of mesoderm forms a tuberculin impar and lateral lingual swelling which forms the anterior 2/3rd of the tongue

Question 50

How is the root of the tongue formed?

Answer 50

-caudally, the copula from the 2nd arche and hypobranchial eminance from the 3rd and 4th arche form the root of the tongue

Question 51

How is the epiglottis formed?

Answer 51

-formed from the 4th and 6th arches

Question 52

Which nerve provides general sensory to the anterior 2/3rd of the tongue?

Answer 52

CNV3-Mandibular N.

Question 53

Which nerve innervates the taste buds on the anterior 2/3rd of the tongue?

Answer 53

CNVII- Facial N. (chorda tympani)

Question 54

Which nerve innervates the root of the tongue?

Answer 54

CNIX (glossopharyngeal)

Question 55

Which nerve innervates the anterior of the epiglottis?

Answer 55

CNX- Vagus N.

Question 56

Chart of branchial arch and what they derive

Answer 56

Question 57

Branchial arche and its structures

Answer 57

Question 58

Picture of muscles of branchial arches

Answer 58

Question 59

Branchial arch and its structures

Answer 59

Question 60

Fate of clefts and pouches

Answer 60

Question 61

Mesenchyme for formation of head region is derived from

Answer 61

Paraxial mesoderm (somites/somitomeres), lateral plate mesoderm, neural crest, placodes

Question 62

Muscles of mastication

Answer 62

Temporalis, masseter, and pterygoids

Question 63

Mandibulofacial dysostosis AKA

Answer 63

Teacher Collin's syndrome or FIRST ARCH SYNDROME

Question 64

Mandibulofacial dysostosis

Answer 64

Autosomal dominant w/ variable penetrance - caused by lack of migration of neural crest into pharyngeal arch 1; produces various facial anomalies (deafness due to malformation of ossicles); normal intelligence but may be mistaken due to deafness

Question 65

Muscles of hyoid arch

Answer 65

Stapedius, stylohyoid, posterior belly of digastric, auricular, and muscles of facial expression

Question 66

Adult derivatives of pharyngeal pouch 1

Answer 66

Epithelial lining of auditory tube and middle ear cavity; tubotympanic recess (lateral/distal = tympanic/middle ear cavity; medial/proximal = auditory/eustachian tube)

Question 67

Adult derivatives of pharyngeal pouch 2

Answer 67

Epithelial lining of palatine tonsils crypts (medial = tonsillar fossa, surface epi of palatine tonsil; lateral = degenerates)

Question 68

Adult derivatives of pharyngeal pouch 3

Answer 68

Inferior parathyroid gland and thymus (dorsal = inf. parathyroid; ventral = thymus); things move caudally

Question 69

Adult derivatives of pharyngeal pouch 4

Answer 69

Superior parathyroid gland, contribute to parafollicular cells of thyroid (dorsal = parathyroid; ventral = degenrates; ultimobranchial body = C-cells/parafollicular cells); things move caudally