T3 Head and Neck

Question 1

From where does the craniofacial region develop?

Answer 1

prechordal area

Question 2

What is the dominant part of the future head region?

Answer 2

forebrain

Question 3

What is the earliest representation of the facial region?

Answer 3

stomodeum

Question 4

Much of the tissue involved in the formation of the facial area is derived from where?

Answer 4

the neural crest

Question 5

Early primordia for the facial region are situated around the stomodeum. The frontonasal prominence consists of what?

Answer 5

forebrain neural crest cells and midbrain neural crest cells

Question 6

Early primordia for the facial region are situated around the stomodeum. The ectodermal nasal placodes form what?

Answer 6

Nasomedial process (from forebrain neural crest) and nasolateral process (from midbrain neural crest).

Question 7

The maxillary and mandibular processes are filled with what type of cells?

Answer 7

neural crest mesencyme

Question 8

What is the name for four pairs of lateral endodermal outpockets from the foregut?

Answer 8

pharyngeal pouches

Question 9

What is the name for the ventral midline endodermal outpocketings from floor of foregut between pharyngeal pouches I and II?

Answer 9

Thyroid diverticulum

Question 10

What is the name for four pairs of ectodermal inpocketings that lie opposite tot he associated pharyngeal pouches?

Answer 10

pharyngeal grooves

Question 11

What is the name for five pairs of mesenchymal masses that lie between the pharyngeal pouches and grooves?

Answer 11

Pharyngeal (branchial) arches

Question 12

What is an aortic arch?

Answer 12

single artery within each pharyngeal arch that connects the ventral aorta to the dorsal aorta

Question 13

In the neural tube, what is the function of the basic signaling center?

Answer 13

• segmentation of cranial neural tube occurs as a result of Hox gene expression.
• segmentation is carried over into the neural crest cells

Question 14

What does the neural tube give rise to?

Answer 14

neural crest tissue

Question 15

In pharyngeal endoderm, patterning is heavily based on what?

Answer 15

exposure to retinoic acid

Question 16

The first pharyngeal pouch is not dependent on retinoic acid. What IS it dependent on?

Answer 16

Otx2

Question 17

What pharyngeal pouches are dependent on retinoic acid? how much?

Answer 17

Second pouch, slightly dependent

Third and Fourth pouches, heavily dependent

Question 18

The pharyngeal endoderm signals the prepatterning of the cranial ectoderm via _____.

Answer 18

FGF8

Question 19

True/False: Pharyngeal arch patterning is dependent on neural crest.

Answer 19

False

Question 20

What is the development of the pharyngeal arches dependent on?

Answer 20

signals from pharyngeal pouches

Question 21

What genes heavily influence dorsoventral patterning in the pharyngeal arches?

Answer 21

DLX genes

Question 22

Signaling from what center is necessary for the development of the neural crest derivatives involved in lower facial morphogenesis?

Answer 22

cranial ectoderm

Question 23

Cranial ectoderm is prepatterned by what from where?

Answer 23

by FGF8 from pharyngeal endoderm

Question 24

Frontonasal ectodermal zone is induced by what from where?

Answer 24

shh from forebrain

Question 25

What is an ectodermal signaling center involving the establishment of dorsoventral gradient of FGF8 (more dorsal) and shh (more ventral)?

Answer 25

frontonasal ectodermal zone

Question 26

facial primordia consist of what?

Answer 26

frontonasal prominence, nasomedial processes, and nasolateral processes

Question 27

Primordia for jaws forms from what number pharyngeal arch?

Answer 27

first

Question 28

Maxillary processes consists of __________ derived from forebrain and midbrain

Answer 28

neural crest

Question 29

Mandibular processes consist of neural crest derived from ______ and _______.

Answer 29

midbrain and hindbrain

Question 30

Subdivision of first arch into upper and lower jaw primordia is dependent on what?

Answer 30

endothelin-1

Question 31

From where is Meckel's cartilage derived?

Answer 31

neural crest cells

Question 32

Around what does the mandible form?

Answer 32

Meckel's cartilage

Question 33

What are the derivatives of Meckel's cartilage?

Answer 33

articular and quadrate

Question 34

What type of joint is the TMJ?

Answer 34

synovial

Question 35

Formation of the TMJ involves what transcription factor?

Answer 35

early expression of Barx-1

Question 36

What comes of the quadrate bone?

Answer 36

moves to middle ear and becomes the incus

Question 37

What comes of the articular bone?

Answer 37

move to middle ear and becomes the malleus

Question 38

The stapes is present in lower vertebrates as the only middle ear bone. From where is the stapes derived?

Answer 38

pharyngeal arch II

Question 39

When does the palate form?

Answer 39

between 6 and 10 weeks of development

Question 40

What does the palate divide?

Answer 40

the common oronasal cavity into a nasal cavity and an oral cavity. these two cavities remain connected together in the adult as the pharynx (oropharynx and nasopharynx)

Question 41

What does the median palatine process (unpaired) form?

Answer 41

primary palate = premaxilla

Question 42

What does the lateral palatine process (paired) form?

Answer 42

secondary palate

Question 43

What tf nasal placodes require for development

Answer 43

pax6 and retinoid

Question 44

Where do the nasal placode develop?

Answer 44

they develop from anterolateral edges of neural plate (before closure)

Question 45

What are nasal pits?

Answer 45

invagination of nasal placodes

Question 46

What is the source of retinoids that stimulate FGF-8 to stimulate proliferation of mesenchyme in nasomedial and nasolateral processes?

Answer 46

nasal pits

Question 47

What are nasal pits surrounded by?

Answer 47

nasomedial and nasolateral processes

Question 48

Where is olfactory epithelium derived?

Answer 48

dorsal epithelium of nasal pits

Question 49

What TF does olfactory epithelium require?

Answer 49

FGF-8

Question 50

What does olfactory epithelium form?

Answer 50

bipolar neurons that project to olfactory bulb

Question 51

What is the dental lamina?

Answer 51

C shaped bands of oral ectoderm overlying neural crest mesenchyme

Question 52

What is a tooth bud?

Answer 52

epithelial downgrowth overlying neural crest mesenchyme and marking position of a single tooth

Question 53

What is the cap stage?

Answer 53

Inverted cup-shaped layer of ectoderm capped by stellate reticulum and covering a mass of mesenchyme = the dental papilla

Question 54

What is the bell stage?

Answer 54

- cone shaped primodium covered by stellate reticulum overlying the enamel organ - Enamel organ: ameloblasts make up the outermost layer of this two layered covering - dental papilla: odontoblasts form the outermost layer of the pulpy mass and lie under and adjacent to the layer of ameloblasts.

Question 55

What is the dental sac?

Answer 55

a condensation of mesenchymal cells around the developing tooth which will form the cementum and periodontal ligament

Question 56

What does Osr2 do?

Answer 56

inhibit BMP-4. If Osr2 is removed, there will be another row of teeth formed on the lingual side of the normal row

Question 57

What do salivary glands arise as?

Answer 57

typical epithelial exocrine glands from oral epithelium

Question 58

What does the development of salivary glands depend on?

Answer 58

interactions between the epithelium and the underlying mesenchyme

Question 59

Branching pattern of salivary glands depends heavily on what?

Answer 59

shh

Question 60

For salivary gland development, the signaling between ______ and ______ occurs within the epithelium rather than between the epithelium and mesenchyme as occurs in other types of glandular development.

Answer 60

shh and FGF