Development of the Pharyngeal Apparatus Flashcards
What makes up the pharyngeal apparatus?
pharyngeal arches, pouches, grooves, and membranes
When do the pharyngeal arches develop?
early in the 4th week
What is the first pair of arches known as?
the primordial jaws
What initiates the formation of the pharyngeal arches?
NCCs migrate away from the dorsal aspect of the developing neural tube and begin to populate ventral areas in what will be the head and neck
Where do cranial neural crest cells migrate from?
forebrain, midbrain, and hindbrain regions in the developing neural tube
what are the three main components of the pharyngeal arches?
core, external lining, internal lining
what is the core of the pharyngeal arches composed of?
mesoderm and mesenchyme
what is the external lining of the pharyngeal arch composed of?
ectoderm
what is the internal lining of the pharyngeal arch composed of?
endoderm
What is mesenchyme
embryonic CT
where does the mesoderm in the core of the pharyngeal arch come from?
it arises from paraxial mesoderm
what does the NCC-derived mesenchyme in the pharyngeal arch form?
all connective tissue in the head, including the dermis and smooth muscle
what does the paraxial mesoderm in the pharyngeal arch form?
forms PA musculature
what does the lateral plate mesoderm in the PA form?
angioblasts that differentiate into endothelium
what does prechordal plate mesoderm in the PA form?
extraocular musculature
What is the cartilage of the first pharyngeal arch also known as?
Meckle’s cartilage
what does the dorsal part of meckle’s cartilage form?
malleus and the incus
what does the ventral part of meckle’s cartilage form?
primordium of the mandible (like a place holder)
what does the perichondrium of meckle’s cartilage form?
anterior ligament of the malleus and the sphenomandibular ligament
what is the cartilage of the 2nd pharyngeal arch also known as?
riechert’s cartilage
what does the dorsal part of riechert’s cartilage form?
stapes and styloid process o the temporal bone
what does the perichondrium of riechert’s cartilage form?
the styloidhyoid ligament
what does the ventral portion of riechert’s cartilage form?
It ossifies to form the lesser cornu/horn of the hyoid bone
What does the third pharyngeal arch cartilage form?
it ossifies to form the greater cornu/horn of the hyoid bone
what is the body of the hyoid bone formed by?
the hypopharyngeal eminence
what does the cartilage of the 4th pharyngeal arch form?
laryngeal cartilages including the epiglottis
what does the cartilage of the 6th pharyngeal arch form?
laryngeal cartilages
Most muscular components of the face arise from what?
paraxial mesoderm
the first pharyngeal arch gives rise to what musculature?
muscles of mastication, mylohyoid, anterior belly of the digastric, tensor veli palatini, and tensor tympani
the second pharyngeal arch gives rise to what musculature?
stapedius and muscles of facial expression
the third pharyngeal arch gives rise to what musculature?
the stylopharyngeus
the fourth pharyngeal arch gives rise to what musculature?
cricothyroid and pharyngeal constrictors