Prenatal & Craniofacial Development- Cox Flashcards by Abagayle Moody

Morphogenesis of the face is a complex 3D process involving:

patterning, outgrowth, fusion and molding of tissues

How well did you know this?

Not at all

Perfectly

at around 22 days (3 weeks), head and neck regions comprise:

nearly half of the embryo

How well did you know this?

Not at all

Perfectly

During the 4th week, ventral mesoderm condenses into a series of segmented bilaterally paired:

mesenchymal swellings

How well did you know this?

Not at all

Perfectly

During the 4th week, ventral mesoderm condenses into a series of segmented bilaterally paired mesenchymal swellings also known as:

pharyngeal (branchial) arches

How well did you know this?

Not at all

Perfectly

There are ultimately ___ pairs of pharyngeal (branchial) arches arising in a ____ order

cranial-caudal

How well did you know this?

Not at all

Perfectly

Cranial-caudal can also be referred to as:

anterior-posterior

How well did you know this?

Not at all

Perfectly

Thinking of the face itself now, initially __ prominences (tissue masses) surround the ___

5; stomodeum

How well did you know this?

Not at all

Perfectly

The first mandibular arch and maxillary processes are both ___

paired structures

How well did you know this?

Not at all

Perfectly

The first mandibular arch and maxillary processes are both paired structures and grow:

Ventro-laterally around the OM

How well did you know this?

Not at all

Perfectly

The oropharyngeal membrane breaks down during:

4th week

How well did you know this?

Not at all

Perfectly

(pharyngeal arch growth) The majority of growth and morphological change in facial tissue masses is driven by:

invading cranial neural crest-derived mesenchyme

How well did you know this?

Not at all

Perfectly

The ____ forms first, then forms into the ___ . Then the ___ splits off

branchial arch 1; mandibular portion; maxillary portion

How well did you know this?

Not at all

Perfectly

contrary to textbook literature, the paired first pharyngeal arches only give rise to ____.

mandibular processes

How well did you know this?

Not at all

Perfectly

____ originate as separate (delayed) swellings rostral to the mandibular processes

maxillary processes

How well did you know this?

Not at all

Perfectly

Maxillary processes occur due to the invasion by a distinct population of:

late migrating CNCC

How well did you know this?

Not at all

Perfectly

Formation and invagination of ____ (thickening of ectoderm) in the frontonasal prominence (FNP) occurs after the maxillary and mandibular swellings occur

nasal placodes

How well did you know this?

Not at all

Perfectly

Induction and invagination of ___ is similar to neural plate induction and invagination

nasal placodes

How well did you know this?

Not at all

Perfectly

(morphogenesis of the midface): there are two types of morphological processes for “joining tissues” including:

merging
fusion

How well did you know this?

Not at all

Perfectly

Joining of two masses already partly in contact

merging

How well did you know this?

Not at all

Perfectly

What structures are involved in the morphological process of “merging”

merging of maxillary and lateral nasal processes
medial merging of mandibular processes

How well did you know this?

Not at all

Perfectly

In morphogenesis of the midface, ___ occurs between the maxillary and lateral nasal processes (MXP & LNP)

merging

How well did you know this?

Not at all

Perfectly

In morphogenesis of the midface, ____ occurs with the mandibular processes (MNP)

medial merging

How well did you know this?

Not at all

Perfectly

In morphogenesis of the midface, merging occurs during the ___ week of human development

5th week

How well did you know this?

Not at all

Perfectly

Joining of two separate tissue masses:

fusion

How well did you know this?

Not at all

Perfectly

During formation of the primary and secondary palates, ____ occurs between the MNP, MXP/LNP:

contact-dependent fusion

Contact dependent fusion between the MNP (medial nasal process), and MXP/LNP (maxillary nasal process/Lateral nasal process) forms the:

primary palate and nares (nostrils)

Contact dependent fusion between the MNP (medial nasal process), and MXP/LNP (maxillary nasal process/Lateral nasal process) forms the primary palate and nares during the ___ week of human development

6th week

The ____ arises later rom the medial aspects of the MXPs leading to palatal shelves

secondary palate

The secondary palate (future roof of mouth) arises later from the medial aspects of the __ which lead to ___.

MXPs; palatal shelves

The secondary palate forms during the ___ week of human development

10th

The secondary palate forms during the 10th week of development through a ___ event

fusion

after immigration of cranial neural crest cells, growth and morphogenesis of the face is controlled by ongoing:

epithelial-mesenchymal interactions

responsible for determining facial form/shape:

cranial neural crest cells

in addition to CNCCs primarily determining facial form/shape, ___ also play a role

ectoderm

How does the ectoderm play a role in determining facial form/shape:

defines boundaries of gene expression

What are two examples of neural expression signals provided by the ectoderm for role in facial form/shape:

Shh & Fgf8

juxta-positioned FGF8/SHH leads to:

frontonasal ectoderm zone (FEZ)

The growth factor secreted by ventral facial ectoderm:

Shh

The growth factor secreted by the dorsal facial ectoderm:

Fgf8

Ectodermal factors instruct:

facial D-V patterning

secreted factors from the FEZ can direct outgrowth of the underlying CNCC and determines:

D-V pattern of FNP

The precise shape of the frontonasal process depends upon pattern information inherent in the:

neural crest

List three other functions of the ectoderm (in addition to gene expression/patterning signals):

1. support and direct outgrowth of facial processes 2. Guides differentiation of CNC through growth factors 3. facilitates fusion of facial processes

fusion between what 3 components of the embryo must occur in order to form the primary palate:

1. medial nasal tissue 2. lateral nasal process 3. maxillary process

for the medial nasal tissue, lateral nasal process, and maxillary process to fuse to form the primary palate, what is absolutely required?

ectodermal cells

Fusion establishes the primary palate which goes on to form the:

alveolus and lip proper

How do we know that fusion of the medial nasal tissue of the frontal nasal process, the lateral nasal process and the maxillary process are improtant?

because defects in this fusion result ini cleft lip and palate

full fusion is required to ensure the ___ is continuous

alveolar bone

third most common birth defect and occurs in ~1 in 700 births world-wide

cleft lip +/- cleft primary palate

forms through a similar fusion mechanism as the primary palate:

secondary palate

When does the primary palate form? when does the secondary palate form?

7th week; 10th week

condensations of CNCC mesenchyme are:

palatal shelves

Secondary palate formation involves: (3)

1. growth of maxillary extensions (either side of tongue) 2. Elevation and rotation 3. medial growth and fusion at midline with nasal septum

___ of the secondary palate begins just before palatal development is complete:

ossification

Palatal shelves are condensations of:

CNCC mesenchyme

What is required in order to have complete mesenchyme over the bridge to form the bony part in the formation of a secondary palate:

movement and disintegration of epithelia

Defects in palatal shelf fusion would result in:

cleft secondary palate

Cleft primary palate occurs in : Cleft secondary palate occurs in:

1/700 births 1/1000 births

Cleft secondary palate can result from:

1. poor growth of shelves 2. failed elevation 3. failed fusion

What is critical for the tongue and secondary palate closure?

critical that the tongue lower to allow the shelves to rotate to a position above the tongue

Macroglossia (enlarged tongue) can provide a physical barrier to:

secondary palate closure

____ is also associated with failed palatal fusion (such as in pierre-robin sequence)

small or retrognathic mandible

A small or retrognathic mandible results in the tongue being:

force backward ad elevated

craniofacial cartilage first appears in the ____ and shortly thereafter in the ____ and ____

mandible; midface & cranial base

Provides structural support for shaping the growing head:

craniofacial cartilage

Unlike the axial skeleton, craniofacial cartilage:

is not typically replaced by bone

Cartilage of pharyngeal arch 1:

Meckel's Cartilage

When does meckel's cartilage arise and what does it form?

7th week of human development; template for the mandible

Pharyngeal arch 1 also contirbutes to two:

ear ossicles (parts of malleus and incus)

If a patient has a mandibular defect, what also should you check for?

inner ear deficiencies

portion of the ear: - derivatives of PA1 and PA2 - intervening pharyngeal cleft - pharyngeal pouch

external and middle ear

portion of the ear: - arises from thickening of ectoderm (otic placode) dorsal to PA3 at the level of the hind brain and subsequent invagination (otic pit)

Inner ear

During the development of the ear, region between PA1 and PA2 undergo a morphological change to create bulge like structures called:

Hillocks of His

Inner and outer ear malformations are often associated wtih:

mandibular defects

ossification of the mandible and maxilla start occurring around day ____ of development

day 52

cranial neural crest cells give rise to the bony structures of the ___ & ___ but not the ____ as those are derived from a mesoderm component

face and frontal bone; NOT parietal bone