Sievert-Head and Neck Development and Superficial Face Anatomy Flashcards
What are the three primordia of head and neck development?
placodes
somites
pharyngeal/branchial arches (clefts and pouches)
What is this:
an ectodermal thickening that forms structures for some of our special senses
placodes
What are the types of placodes?
olfactory placode
lens placode
otic placode
What do preotic somites turn into?
extraocular muscles
what do postotic somites turn into?
tongue muscles
What is the nasal placode induced by?
adjacent olfactory bulb of the forebrain
What does the nasal placode form?
the primary olfactory epithelium (i.e cell of smell)
So you have the olfactory bulb which makes the nasal placode which forms the primary olfactory epithelium which then pierces what?
the olfactory bulb through the ethmoid bone (cribiform plane)
What does the olfactory bulb have within it that connects with primary neurosensory cells?
secondary neurosensory cells
How does the lens placode form?
the optic cup (neuroectoderm from diencephalon) induces a thickening of the surface ectoderm which forms the lens placode. (i.e the optic cup pac mans the ectoderm to create a lens)
Does the lens placode contain sensory cells?
no
What are the three parts to the ear?
external, middle and inner ear
What does the otic placode make?
the inner ear
labryrinth and sensory neurons of cranial nerve 8
What sensory neurons are made from the otic placode of cranial nerve 8?
hair cells
What is the membranous labyrinth of the otic placode of cranial nerve 8?
utricle, semicircular canal, endolymphatic duct
What is significant about the development of the inner ear and why is this worrisome?
it is very slow
makes it susceptible to environmental defects
Cranial nerves that carry sensory info will have a cranial nerve ganglion (blank) the CNS where there would be no synpase present.
outside
What becomes the future middle ear?
the pharyngeal pouch lined by the endoderm of the pharynx
What becomes the external ear?
the surface ectoderm of the first pharyngeal cleft (groove)
How does the tympanic membrane form?
three germ layers endoderm, mesenchyme, ectoderm meet up and form the tympanic membrane : )
What are masses of mesoderm that form skeletal muscles?
somites
(blank) somites from muscles that move the eye not the muscles of the iris or the lens.
preotic
(blank) somites form muscles of the tongue
postotic
What are extraocular muscles?
muscles outside the eyeball that move the eyeballe (i.e. levator ptosis)
What CN take care of all extraocular eye muscles?
3,4,6
What are fibers that innervate muscles that came from somites?
general somatic efferents
What are the fibers that innervate muscles that are associated with viscera?
general visceral efferents
Whats another name for pharyngeal arches?
branchial arches
What are the fibers that innervate muscles that come from branchial arch of mesenchyme (no different than skeletal muscle)?
branchial motor efferents
What cranial nerve are used for extraocular muscles?
What cranial nerves are used for ear?
3,4,6
8
Masses of mesenchyme tissue that flank the developing gut appear around the (blank-blank) week.
4th-5th
Pharyngeal arches appear in (blank) to (blank) direction.
cranial to caudal direction
Each pharyngeal arches is associated with what three things?
artery, nerve, and bony structure
Describe the germ cell lining of a pharyngeal arch
ectoderm on outside, endoderm on inside, neural crests cells in bony structures
(blank) cells exist in the core of pharyngeal arches to contribute to skeletal components of the face.
Neural crest
Clefts are on the (blank) while pouches are on the (blank)
outside
inside
What four things will pharyngeal arches create?
muscle
bone/cartilage
skin from overlying ectoderm
lining of the gut from the lining endoderm
What does the maxillary process (from first arch) form?
the maxilla, zygomatic bone and part of the temporal bone.
Which arch forms the upper and lower jaws?
first
What all does mandibular process form?
the mandible, malleus, and incus
What skeletal element does the second arch form?
the hyoid arch froms the lesser horn of hyoid bone, styloid process and stapes
What skeletal element does the third arch form?
the rest of the hyoid bone that the second arch did not complete
What skeletal element does the fourth arch form?
nothing alone but with the 6th it fuses to form laryngeal cartilgae
What skeletal element does the first arch form?
maxillary process (maxilla, zygomatic bone, temporal bone) and mandibular process (mandible, malleus, and incus)
What kind of muscles does the first pharyngeal arch create?
muscles of mastication
What kind of muscles does the 2nd pharyngeal arch create?
muscles of facial expression
What kind of muscles does the 4th/6th pharyngeal arch create?
muscles of the pharynx, larynx, and palate
The (blank) lining each pharyngeal arch is innervated by the nerve of that arch
endoderm
Which nerve innervates the first pharyngeal arch?
cranial nerve 5
On the anterior 2/3rds of the tongue, what happens to the the second arch? What does this mean about its nerve innervation?
it gets overgrow by arch 1 and thus is innervated by cranial nerve 5
Which nerve innervates arch 3?
glossopharyngeal (CN 9)
Which nerve innervates arch 4?
vagus and superior laryngeal nerve
Which nerve innervates arch 6?
vagus and recurrent laryngeal
What type of germ layer is the anterior 2/3rds of the tongue made up of?
ectoderm
What type of germ layer is the posterior 1/3 of the tongue made up of?
endoderm
What arch gives sensory innervation to the epiglottis?
arch 4
What arch gives sensory innervation to the root of the tongue?
arch 3
What arch gives sensory innervation to the body of the tongue?
arch 1
What separates the anterior tongue from the posterior tongue?
sulcus terminalis
The first pouch merges with the first cleft to make the (blank).
auditory tube /eustachian tube and middle ear cavity
What does the second pouch make?
the palantine tonsil
What does the third pouch give rise to?
the inferior parathryoid gland to the thymus
What does the fourth pouch give rise to?
the superior parathyroid gland
What does the fifth pouch give rise to?
C cell of the thyroid gland