EMBRYO: Face, Nose

Question 1

At Week ___, Facial Primordia is established

Answer 1

4

Question 2

What are the 5 facial primordia

Answer 2

1 frontonasal prominence

2 maxillaary prominences

2 mandibular prominences

Question 3

The 5 facial primordia develop where?

Answer 3

as bulging prominences around the stomodeum

Question 4

Where is each facial primordia (week 4) in relation to th estomoedum?

Answer 4

frontonasal is rostral

maxillary is lateral

mandibular is caudal

Question 5

Skeletal elements of the face are from ____

Answer 5

neural crest cells

Question 6

Striated muscle, dermis, endothelium of blood vessels in the face develop from ____

Answer 6

paraxial mesoderm

of occipital somites to the tongue

Question 7

What separates the primitive oral cavity from the development GI tract?

Answer 7

buccopharyngeal membrane/oral membran/oropharyngeal membrane

Question 8

When does the buccopharyngeal membranedisintegrate?

Answer 8

Early week 5

Question 9

During the EMBRYONIC PERIOD (weeks 4-8), what major developments occur in the face?

Answer 9

most facial structures develop during weeks 4-8

Question 10

During FETAL PERIOD, what happens do the cranium?

What affect does this have on the eyes position/

Answer 10

cranium expands to accompany growing brain, causing eyes to shift anteriorly and medially

Question 11

During FETAL PERIOD, what happens to the ears?

Answer 11

move superiorly

Question 12

During FETAL PERIOD, what happens to the nose?

Answer 12

becomes more prominent

Question 13

During FETAL PERIOD, what is the proportion of the face skeleton relative to the rest of the skull?

Answer 13

at first, facial skeleton appears small in comparison to the rest of skull

proportions become more normal when maxilla/mandible grow to allow space for teeth and once we acquire the paranasal sinuses

Question 14

Nasal placodes appear at week __

Answer 14

4

Question 15

The nasal placodes are 2 ______ thickenings within the ____ prominence

Answer 15

2 ectodermal thickenings within the frontonasal prominence

Question 16

Surrounding ___ of the nasal placodes proliferates

Answer 16

mesenchyme

Question 17

How do the medial and lateral nasal prominences form?

Answer 17

mesenchyme surrounding the nasal placodes proliferates, forming elevations

Question 18

Mesenchyme surrounding nasal placodes proliferates and forms elevations. What are they

Answer 18

2 medial nasal prominences

2 lateral nasal prominences

Question 19

Nasal pits can be seen at week __

Answer 19

5

Question 20

Nasal pits deepen and expand in what direction

Answer 20

dorsally

Question 21

what part of nasal placode sinks down into underlying mesenchyme creating a depression (forming the nasal pit)

Answer 21

epithelium

Question 22

Why do nasal pits appear even more sunken in than they are?

Answer 22

because nasal pits begin to deepen simultaneously to the medial/lateral prominences forming

(week 5)

Question 23

What significant facial developments occur month 2-3?

Answer 23

facial features are more pronounced

eyes move more mredially

ears more superiorly

FIRST OSSIFICATION CENTER OF THE SKULL

Question 24

The first ossification center of the skull appears during month ___

Answer 24

2-3

Question 25

What is the oronasal membrane?

Answer 25

membrane separating the nasal cavity from the oral cavity

Question 26

When does the oronasal membrane rupture?

Answer 26

end of week 6

Question 27

What happens after the oronasal membrane ruptures at the end of week 6?

Answer 27

after the oronasal membrane has ruptured (week 6), the nasal cavities communicate with the oral cavity thru the PRIMORDIAL CHOANAE

Question 28

What ist he primordial choanea?

Answer 28

This is how the oral cavity and the nasal cavities initially communicate with each other after hte rupturing of the oronasal membrane

Question 29

What establishes the definitive choanea?

Answer 29

the development of the secondary palate establishes the definitive chonae which separates nasal cavity from nasopharynx

Question 30

Where is the choana found?

Answer 30

at the posterior extent of the nasal cavity

Question 31

Nasolacrimal groove is seen week __

Answer 31

6

Question 32

The nasolacrimal groove is a cleft between what 2 prominences

Answer 32

nasolacrimal groove is cleft between LATERAL NASAL PROMINENCES and MAXILLARY PROMINENCES

Question 33

When is the nasolacrimal groove lost?

Answer 33

when the lateral nasal prominences and the maxillary prominences fuse together

Question 34

What happens to the nasolacrimal groove?

Answer 34

It forms a rod and is canalized

Question 35

When the nasolacrimal groove becomes a rod, what does it do?

Answer 35

it separates from the surface adn then canalizes into the nasolacrimal DUCT

Question 36

What is happening (in terms of germinal layers) during the formation of the nasolacrimal duct (from the nasolacrimal groove)

Answer 36

ectoderm proliferates into underlying mesenchyme

Question 37

What is at the superior end of the nasolacrimal duct?

Answer 37

nasolacrimal SAC | a dilation of the nasolacrimal duct

Question 38

Where is the nasolacrimal sac?

Answer 38

this is a dilation of the nasolacrimal duct it is found at the superior end of the duct

Question 39

The inferior end of the nasolacrimal duct opens up into the ____

Answer 39

inferior meatus of the nasal cavity

Question 40

The nasolacrimal duct runs from __ to the ___

Answer 40

from the orbit to the inferior meatus of the nasal cavity **this is why our nose runs when you cry

Question 41

What structure is responsbile for our nose running when we cry?

Answer 41

nasolacrimal duct | because it runs from the orbit to the inferior meatus of the nasal cavity

Question 42

Mandibular prominence fuse at ____

Answer 42

the midline

Question 43

Maxillary prominences grow, move medially, compress the nasal prominences at the midline... during week ___

Answer 43

6

Question 44

How does the growth of the maxillary prominences effect the medial nasal prominences?

Answer 44

WEEK 6 max prominences growth causes medial nasal prominences to compress together and eventually fuse (week 7)

Question 45

Medial nasal prominences fuse week ___

Answer 45

7

Question 46

What causes the medial nasal prominences to fuse week 7?

Answer 46

maxillary prominence growth causes medial nasal prominences to compress and fuse week 7

Question 47

Week 7, medial nasal prominences fuse creating ____

Answer 47

1 intermaxillary segment

Question 48

What are the components of the intermaxillary segment?

Answer 48

philtrum, premaxillary part of maxilla, 4 incisors and associated gingiva, and primary palate

Question 49

The intermaxillary segment is formed by what

Answer 49

the fusing of the medial nasal prominences

Question 50

What are the lateral palatine processes?

Answer 50

mesenchymal outgrowths they are medial extensions from the maxillary prominences

Question 51

lateral palatine processes appear at week ___

Answer 51

6

Question 52

Lateral palatine processes project in what direction at first

Answer 52

inferomedially

Question 53

Why do lateral palatine processes project inferomedially at first

Answer 53

to make room for the growing tongue

Question 54

The lateral palatine processes ultimately fuse together to form

Answer 54

the secondary palate

Question 55

After the tongue is formed, what happens to the lateral palatine processes

Answer 55

they move horizontal and fuse with each other, primary palate and nasal septum

Question 56

What embryological structures is the hard palate made up of?

Answer 56

primary palate and anterior most part of secondary palate

Question 57

What embryological structures are the soft palate and uvula made up of?

Answer 57

the most posterior part of the secondary palate

Question 58

What ossifies/what does not ossify (hard/soft palate)

Answer 58

hard palate ossifies soft palate does not ossify

Question 59

Cleft lips/palates are caused by _____

Answer 59

failure of medial nasal prominences to fuse with maxillary prominences

Question 60

Where do cleft palates/lips occur?

Answer 60

these are ANTERIOR palatal defects

Question 61

Cleft lips can be ___

Answer 61

unilateral, bilateral, midline

Question 62

Cleft palates are between ____

Answer 62

primary and secondary palates