development of the face Flashcards
What are the five processes involved in the development of the face?
Face develops from one fronto-nasal process, two maxillary processes, and two mandibular processes.
From where does the maxillary process develop?
It is a forward growth of the dorsal end of the 1st pharyngeal arch.
From where does the mandibular process develop?
It is a forward growth of the ventral end of the 1st pharyngeal arch.
What is the stomodeum?
It is the primitive cavity that forms the nasal and oral cavities.
What is the role of the bucco-pharyngeal membrane?
It ruptures to allow continuity between the oral and pharyngeal cavities.
What is the nasal placode?
A rounded thickening in the lower lateral parts of the fronto-nasal process.
What forms the nasal pits and prominences?
Invagination of the nasal placode forms nasal pits, which are surrounded by medial and lateral nasal prominences.
What is the intermaxillary segment?
A structure formed from fused medial nasal prominences.
What does the intermaxillary segment develop into?
Middle part of the nose, philtrum, part of the upper jaw carrying upper four incisors, and the primary palate.
What separates the maxillary process from the fronto-nasal process?
The naso-lacrimal groove.
What forms inside the naso-lacrimal groove?
A cord of ectodermal cells that later canalizes to form the naso-lacrimal duct.
What does the upper end of the naso-lacrimal duct develop into?
The lacrimal sac.
What happens when the maxillary process fuses with the fronto-nasal process?
It covers the naso-lacrimal duct.
What is the lower boundary of the nasal pit formed by?
The maxillary process.
What separates the maxillary processes from each other?
The intermaxillary segment.
What forms when the maxillary process fuses with the mandibular process?
The cheek.
What is the palatine process, and what does it form?
An inward projection of the maxillary process that forms the secondary palate, dividing the stomodeum into the upper nasal and lower oral cavities.
What does the maxillary process contribute to?
Upper part of the cheek, upper lip except philtrum, upper jaw except the part carrying upper incisors, and most of the hard palate.
What does the mandibular process develop into?
Lower part of the cheek, the entire lower lip, lower jaw, and floor of the mouth.
What forms the primary palate?
The intermaxillary segment of the fronto-nasal process.
What forms the secondary palate?
Palatine shelves of the maxillary processes.
What does the secondary palate develop into?
Most of the hard palate and the soft palate.
What does the hard palate receive during development?
A downward growth of the nasal septum.
