Orofacial Morphogenesis (Exam 1) Flashcards
What two Adult facial features come from the first PA?
- Mandibular region
2. Maxillary region
Which adult facial region is not derived from an arch
Frontonasal region
The checks, upper jaw, upper lip, secondary palate are derived from:
1st PA
The lower jaw, lower lip are derived from:
1st PA
What is the Intermaxillary segment composed of?
Philtrum of lip; Primary palate (premaxilla bone)
The epiglottis is derived from the:
4th PA
The Cricoid cartilage is derived from:
6th PA
The secondary Palate is derived from the:
Palatine bone
The Primary palate is derived from:
Premaxilla
What is the conchae?
Increases air circulation: Is an internal structure from the lateral inside wall
Are bones covered with nasal mucosa. Increases surface area:
Superior and middle conchae are downward extensions of the ethmoid bone
Inferior concha: attaches to maxilla (1st arch)
What is the Nasal septum?
Medial wall: It is part of the anatomical boundaries of the nasal cavity. It runs from roof to floor and divides cavity into two chambers
Comprised of:
- Septal cartilage (SC)
- Perpendicular palate of ethmoid bone (PPE)
- Vomer Bone (VR) ** different embryonic origin (1st Arch)
What is a Meatuses?
Opening below each concha; serves as a connection between nasal cavity and paranasal sinuses
What forms the floor of the nasal cavity?
Formed by the palate and soft palate
What forms the roof of the nasal cavity?
Cribrifomr plate of the ethmoid bone, lined with olfactory epithelium (Ethmoid bone is key to nose)
What are the openings of the Nasal cavity?
Anterior: Nares (Nostrils) = anterior aperture
Posterior: Choana= posterior aperture/opening of nasal cavity leading to nasopharynx and auditory tube
Which part of the nose originates from Ectomesenchyme? (Hint: Two)
- Frontonasal Process/prominence (FNP): (Ectomesenchyme -> Forebrain)
- Anterior cranial base/ Cartilaginous nasal capsule-
Which part of the nose originates from Ectoderm?
- Nasal sensory placode (thickening) -> Nasal pit (depression)
What will ossify to form the Ethmoid bone?
Cartilaginous anterior cranial base = floor of skull that supports the forebrain will ossify to form the ethmoid bone
How does the External regions of the nose originate?
NC from forebrain migrate to FNP -> Proliferate as ectomesenchyme
How does the frontonsasal process of the nose originate?
FNP forms into medial and lateral nasal processes -> CT/cartilage/bones of external nose
How do the internal regions of the nose originate?
Anterior cranial base forms a cartilaginous nasal capsule (gray) -> ossifies to form the future Ethmoid bone which contributes to most structures in nasal cavity
What is a Sensory Placode?
Ectodermal thickening in the 4th week that differentiates into the epithelial structures of the olfactory, optic, otic, sense organs: Neural crest cells contribute and direct differentiation
What structures are recognizable structures in embryo during the 5th-12th week?
- Nasal sensory placode: Forms nasal epithelium
- Nasal pit formation: Forms cavity
- Medial and lateral nasal processes are visible: tissue surrounds nasal pit
- Nasolacrimal groove (7th week): Becomes Nasolacrimal duct and sac
- Medial nasal process fuse together to form: Tip and bridge of external nose
- Lateral nasal process fuses with maxillary process to form: Side of nose forms alar cartilage and lateral cartilage
What forms the Paranasal sinuses?
The Nasal pit (ectoderm) invaginate to form the nasal cavity and later the paranasal sinuses
What differentiates into respiratory (PSCC) and Olfactory epithelium?
Ectoderm lining the cavity will differentiate into Respiratory and olfactory epithelium and glands *olfactory epithelium only in roof of nasal cavity = epithelium contributes to mucosa
Cartilaginous nasal capsule develops from:
The anterior region of the skull floor (future ethmoid bone) and grows downward.
Will form the Nasal septum and superior and middle conchae
What is the Nasal septum?
(Midline): A medial nasal septum grows down inferior from roof of cavity/floor of skull (ethmoid)-> Separates the cavity into two chambers:
- Part of nasal septum remains as hyaline cartilage (septal cartilage)
- Part ossifies by endochondral ossification to form the perpendicular plate of the ethmoid bone
What is the Superior and middle conchae?
They develop as lateral outgrows of the cartilaginous capsule.
A meatus develops below each conchae; The meatus invaginate outward from the nasal cavities to form the paranasal sinuses
** Interior nasal conchae different origi n: Derived from the maxillary bone– 1st PA maxilla*****
What is the germ layer of the ventral surface of tongue?
Endoderm
What is the germ layer of the superior concha and olfactory epithelium?
Ectoderm
Ectoderm forms epithelium associated with:
Mucosa of oral cavity, anterior 2/3 tongue and nasal cavity
*Excludes floor of mouth/ventral tongue
Endoderm forms epithelium associated with:
Mucosa of pharynx and larynx
- Pharynx includes nasopharynx, oropharynx, laryngopharynx
What is different about the larynx/laryngopharynx?
The larynx is PSCC but the laryngopharynx is SSNK (Vocal cord)
Describe Olfactory Mucosa:
Located in roof and superior conchae
- Epithelium: PSCC
- Cell types: Ciliated olfactory cells (bipolar neurons); Basal cells (regenerative); Supporting cells
- –Ectoderm ^^
- Lamina propria/Submucosa: Well vascularized, Pure serous (Bowman’s glands)
CT= Ectomesencymye
Describe Nasal (Respiratory) mucosa:
Located on cavity walls, floor and sinuses:
- Epithelium: PSCC
Cell Types: Ciliated columnar cells; Basal cell; Goblet cell (Mucus producing)
—- Ectomesenchyme ^^^^ - Lamina program/submucosa: We’ll vascularized, Pure mucous glands, Seromucous (mixed secretion) glands
—— Ectoderm^^^
Mucosa of Nasal cavity wall exhibits:
- Thicker mucosa
- Increase # in goblet cells
- Increase # seromucous glands
Medial Nasal process of frontonasal = (embryonic/developmental origin) forms:
- Nose- external: Bridge (nasal bones) and tip of nose
- Also forms: Intermaxillary segment -> Philtrum of lip and primary palate
Lateral nasal process of frontonasal (Embryonic/developmental origin) forms:
- Nose- External: Alar cartilage; Lateral nasal cartilage (side of nose)
Cartilaginous Nasal Capsule is the embryonic origin of:
Internal nasal structures
Medial part of nasal capsule forms:
Nose: Internal -> forms bony medial nasal septum and cartilaginous nasal septum
**Cartilaginous nasal capsule is a part of the floor of the developing skull; the midline the capsule forms cribriform plate of the ethmoid bone. The perpendicular plate o the ethmoid grows down from the cribriform plate to form part of the nasal septum that ossifies and a part that remains cartilaginous
Lateral part of nasal capsule forms:
Nose: Internal: -> forms superior and middle conchae of lateral nasal wall
The Nasolacrimal groove (embryonic/developmental origin) forms:
The nasolacrimal duct/ lacrimal sac.
Groove between lateral nasal and maxillary process and extends from lacrimal sac at the lower corner of eye to nasal cavity– Drains into inferior meatus
The maxillary process of 1st arch is the embryonic/developmental origin for:
- External: Lateral soft issue region of upper lip, cheeks
- Internal: Maxilla; secondary palate (palatine process); lacrimal, zygoma, vomer, inferior concha, Palatopterygo-quadrate cartilage -> Incus (middle ear bone)
Mandibular process of 1st arch is the embryonic/developmental origin for:
External: Soft tissue of lower lip, chin
Internal: Mandibule, TMJ, MEckel’s cartilage -> Malleus (middle ear bone)
How does the inferior concha develop?
Develops as outgrowth from maxilla bone
Cartilages of first arch will undergo:
Endochondral ossification to form incus, malleus, respectively
