Exam 2 Davenport Intro to Pharyngeal Arches

Question 1

After the head folds, the buccopharyngeal membrane resides:

Answer 1

under the head fold/frontonasal process

Question 2

When does the buccopharyngeal membrane rupture?

Answer 2

Around 28 days

Question 3

When do the arches begin to develop?

Answer 3

Early in the 4th week when neural crest cells migrate into the future head and neck region

Question 4

Arches ____ are visible at the end of the 4th week

Answer 4

1-4

Question 5

Arch ____ are rudimentary

Answer 5

5 and 6 (5th does not form, 6th is variable in visibility)

Question 6

When neural crest cells migrate to the head and neck region, the mesoderm that is already there becomes:

Answer 6

somatic mesoderm

Question 7

Neural crest cells are also known as:

Answer 7

ectomesenchyme

Question 8

What type of mesoderm gives rise to the muscles of mastication and some of the bony structures?

Answer 8

Somatic mesoderm

Question 9

In general, what do the neural crest cells give rise to?

Answer 9

Teeth, connective tissue, glands of the oral cavity, components of the tongue

Question 10

Arch components

Answer 10

• Core of mesencyme with ectoderm on the outer surface and endoderm on the inner surface
• aortic arch (2 dorsal aorti)
• cartilage rod
• muscular component
• cranial nerve

Question 11

What are found between each arch?

Answer 11

Webbing; pharyngeal grooves and pouches

Question 12

At pharyngeal grooves and pouches, there is no:

Answer 12

intervening mesenchyme/neural crest –> these membranes are 2 layers thick

Question 13

The pharyngeal arches are ____ structures and eventually come back to ____

Answer 13

bilateral; midaxial symmetry (grow toward each other and fuse)

Question 14

Mandibular prominence vs. maxillary prominence - how do they grow toward each other

Answer 14

1. mandibular simply fuses at mandibular symphysis
2. maxillary prominence wants to do the same thing but there is resistance from the frontonasal process

Question 15

Muscles of mastication come from:

Answer 15

arch 1

Question 16

muscles of facial expression come from:

Answer 16

Arch 2

Question 17

Stylopharyngeus is derives from:

Answer 17

Arch 3

Question 18

Pharyngeal constrictors are derived from:

Answer 18

Arch 4

Question 19

Intrinsic laryngeal muscles are derived from:

Answer 19

Arch 6

Question 20

Facial primordia appears?

Answer 20

Early in the 4th week around the primordial stomodeum

Question 21

Facial primordia arises from:

Answer 21

Inductive influence of POC and ROC

Question 22

The first arch is further divided into:

Answer 22

Maxillary and mandibular prominence

Question 23

Nasal placodes form due to:

Answer 23

Induction of outgrowing olfactory bulbs

Question 24

The nasal placodes go on to:

Answer 24

Invaginate and form the primitive nasal cavity

Question 25

The primitive nasal cavity contains/nasal prominences:

Answer 25

Nasal pit, lateral and medial nasal processes

Question 26

The eyes begin to form due to:

Answer 26

Induction of the optic nerve growing out

Question 27

The facial primordia contains:

Answer 27

Single frontonasal process
2 maxillary prominences
2 mandibular prominences

Question 28

The _____ runs from the corner of the eye to the nasal cavity. If this structure doesn’t form properly, ____ can result

Answer 28

Nasolacrimal duct; oblique facial cleft

Question 29

Nasal placodes appear _____

Answer 29

near the end of the 4th week

Question 30

Auricular hillocks appear ____

Answer 30

near the end of the 5th week

Question 31

Nasolacrimal grooves appear ____

Answer 31

near the end of the 6th week

Question 32

Mid nasal intermaxillary segment forms:

Answer 32

1. middle part of the philtrum
2. premaxilla/associated gingiva
3. primary palate

Question 33

First pharyngeal groove gives rise to:

Answer 33

External auditory canal

Question 34

First pharyngeal membrane becomes:

Answer 34

Tympanic membrane

Question 35

First pharyngeal pouch gives rise to:

Answer 35

inner ear

Question 36

Frontonasal process gives rise to:

Answer 36

forehead, dorsum and apex of nose

Question 37

Lateral nasal process (LNP) gives rise to:

Answer 37

sides (alae) of the nose

Question 38

MNP gives rise to:

Answer 38

nasal septum

Question 39

Maxillary prominence gives rise to:

Answer 39

Upper cheek, most of upper lip

Question 40

Mandibular Prominence gives rise to:

Answer 40

chin, lower lip, lower cheek

Question 41

What forms between the maxillary and mandibular processes?

Answer 41

Odontogenic epithelium

Question 42

True or false: all upper teeth are derived from the maxillary prominence

Answer 42

False - the 4 upper incisors come from the pre maxilla (1 central/lateral from each medial nasal process)

Question 43

The primary palate forms from:

Answer 43

intermaxillary segment/premaxilla which is formed from the median nasal processes

Question 44

Primary palate contains:

Answer 44

• 4 maxillary incisor teeth
• incisive foramen

Question 45

Secondary/definitive palate is formed from:

Answer 45

lateral palatal shelves from the maxillary prominences which fuse with the nasal septum

Question 46

What is the most posterior aspect of the primary palate?

Answer 46

Incisive foramen

Question 47

What separates oral cavity from nasal cavity?

Answer 47

Primary and secondary palate which need to fuse along the midline

Question 48

How do the lateral palatal shelves grow above the developing tongue?

Answer 48

Hyaluronic acid allows increased turgor pressure to flip the lateral shelves above the tongue

Question 49

Depression of the tongue occurs due to:

Answer 49

Muscular contraction of the oral cavity

Question 50

In the pre maxilla, there are __ potential cleft spots:

Answer 50

• between maxillary process and medial nasal process (2)
• between the 2 medial nasal process

3 total

Question 51

If cleft involves the palate, what is a major concern:

Answer 51

Airway and nutrition