Development Of The Face Flashcards
The face primordial appears when and where
Early in the 4th week and around the stomodeum
How may fascia primordial appear as prominences around the stomodeum; name them
5
> the single frontonasal prominence
> the paired maxillary prominences
> the paired mandibular prominences
The paired facial prominences are derivatives of
1st pharyngeal arch
The prominences are produced mainly by what
Proliferation of neural crest cells
The neural crest cells migrate from the —— and —— of the neural fold into the pharyngeal arches during what week
Mesencephalon
Rhombemceohalon
Fourth week
The —— which are two bilateral oval thickening in the surface of the ectoderm of the frontonasal prominence appear by why week
The nasal placodes, The end of 4th week
The nasal placode (or olfactory placode) gives rise to the olfactory epithelium of the nose. Two nasal placodes arise as thickened ectoderm from the frontonasal process. They give rise to the nose, the philtrum of the upper lip, and the primary palate.
Nasal placodes are primordial of what
The nose and nasal cavities
The shape of the nasal placodes are initially —— then later become ——
Convex
Stretched to produce a flat depression on each placodes
Mesenchymes in the margins of the placodes proliferate, producing a horse-shoe shaped elevations called
Medial and lateral nasal prominences
Afterwards, the nasal placodes lie in depression called
Nasal pits
The nasal placodes lie in the depression called
Nasal pits
These pits are the primordial of the what
Anterior nares (nostrils) and nasal cavity
What is the major source of the CT components including muscles, cartilages, bone and ligaments in the facial and oral regions
Mesenchymal cells
The frontonasal prominence is formed of 2 parts; name them
Frontal part: from the forehead
Nasal part: from therostral boundary of the stomodeum
The paired maxillary prominences forms what
Lateral boundaries of the stomodeum
The paired mandibular prominences constitute what
The caudal boundary of the primitive mouth
When does the medial nasal prominence merge with each other and either the maxillary and lateral nasal prominence?
7th and 8th week
Merging of the medial nasal and maxillary prominence im results in
Continuity of the upper jaw and upper lip stomodeum and separation of the nasal pits from the stomodeum
What are the first parts to form the face and form
Lower jaw and the lower lips
The formation of the lower jaw and lower lips are a result of
Merging of the medial ends of the mandibular prominences in the median plane
Failure of the merging of medial ends of the mandibular prominence in the median plane causes what
Median cleft of the lower lip (very rare condition)
Each lateral nasal prominence is separated from the maxillary prominence bt a cleft called
Nasolacrimal groove
The nasolacrimal duct develops from where?
The rodlike thickening of ECTODERM in the floor of the nasolacrimal groove
This thickening of ectoderm gives rise to a ——- that separates from the ectoderm and sinks into the mesenchyme
solid epithelial cord
What forms the nasolacrimal duct?
Cell degeneration which causes the epithelial cord to canalize
What causes oblique cleft lip
What causes midline cleft lip
The failure of the medial nasal prominence and maxillary prominences to fuse
