Embryology- Head and Neck, Cranial Nerves Flashcards
What tissues are the pharyngeal arches derived from?
What do they interact with
General Mesoderm; they interact with neural crest cells
Glands and mucosae, original tissue and what they interact with
Endoderm, interact with neural crest ectoderm
Brain, embryologic origin tissue
Ectoderm
Cranial nerves, origin
ectoderm
Placodes
What are they? What tissue are they derived from?
- Discs that appear on ectoderm, sensory specialization occurs here
- Later form eye lens, ear spaces, nasal cavity, neurogenic structures
- All derived from ectoderm
Head somites
What are they (specific m.m.)?
What tissue are they derived from?
Derived from head mesoderm
- eg. eye muscles, tongue, SCM, trapezius
What tissues make up the skull? What to they become? What is the embryologic tissue they are derived from?
All derived from mesoderm. Different precursors eventually become bone.
Endochondral cartilages (later bone replaces it)- make up anterior and posterior neurocranium- vertebrae, ethmoid, nasal conchae, central sphenoid
Intramembranous ossification desmocranium (dermal bones)- interact with neural crest cells- make frontal, parietal, occipital, and zygomatic bones
Notochord (makes basisphenoid and basioccipital bones), vertebrae, endochondral cartilages mix
How does endochondral cartilage in skull become bone?
Bone tissue comes above and below it, later bone fills in
The notochord makes part of which bones?
Basisphenoid and basioccipital bones
- Neurocranium is also involved with formation of these bones
Which cranial nerves are associated with placodes?
I- Olfactory
II- Optic
VII- Vestibulocochlear
-They are all sensory nerves–> “special afferent”
Which cranial nerves are associated with head somites and somitomeres?
III- Oculomotor IV- Trochlear VI- Abducens XI- Accessory XII- Hypoglossal
-They are all motor nerves–> all are general somatic efferent AND CN III is also general visceral efferent
Which cranial nerves are associated with pharyngeal arches?
V- Trigeminal
VII- Facial
IX- Glossopharyngeal
X- Vagus
- These are “mixed” nerves, sensory and motor component
- -> All are special afferent (SA), General somatic afferent (GSA), General visceral afferent (GVA), , General visceral efferent (GVE), Special visceral efferent (SVE)
What does the nasal placode form?
Mucosa of nasal capsule
What does the lens placode form?
Lens of the eye
What does the otic placode form?
Vestibular and cochlear parts of the ear?