Head and Neck Primordia Flashcards
What structure does the olfactory placode give rise to?
olfactory epithelium
What structures does ectoderm give rise to?
Special sensory placodes
Surface ectoderm
Optic nerve primordia
Optic cup
Optic Cup
Two layered cup of ectoderm
Extension of developing brain
special sensory neurons for vision
Occulomotor Nerve Primordia
Preotic Somitomeres
What structures does surface ectoderm form?
Epidermis of skin of head and neck
Mucous membranes of oral and nasal cavities
What is stomodeum and what structures does it form?
Invagination of ectoderm at site of oral membrane
Oral and nasal cavities
Sensory placodes are thickenings of _______?
epithelium
The optic cup is an ectodermal extension of the ______.
neural tube (developing brain)
What three structures does mesoderm give rise to?
Head somites
Head mesenchyme
Pharyngeal (branchial arches)
Head somites develop exclusively into _____?
striated muscle
Preotic somites develop into _______.
extraoccular eye muscles
Which cranial nerves supply preotic somites?
Occulomotor (III)
Trochlear (IV)
Abducens (VI)
_______ become the intrinsic muscles of the tongue.
Postotic somites
What nerve supplies postotic somites?
Hypoglossal nerve (XII)
What are pharyngeal (branchial) arches
Bars of mesoderm that flank the primitive oral cavity and pharynx
Pharyngeal branchial arches flank _________ and _________
oral cavity, pharynx
What is head mesenchyme?
loose, mesodermal, connective tissue surrounding the brain
Head mesenchyme is derived from __________/
ectodermal neural crest
________ provides general sensory fibers to head mesenchyme structures.
Trigeminal nerve
What structures does head mesenchyme give rise to?
Non-retinal parts of eyeball
Dermis of facial skin
Bones of neurocranium
Meninges
Skin of the back of the head and neck receives sensory innervation and sympathetics from ____________.
Cervical spinal nerves
The front of the neck is innervated by _______.
cranial nerves
The opthalmic nerve provides general sensory neurons to _______, ________, and _______.
forehead, external nose, orbit
The maxillary nerve supplies the ____, _____, _______.
cheeks, nasal cavity, upper jaw
What structures do pharyngeal arches give rise to?
Muscles, bones and other tissues of the head and neck
The ___________ forms skin of the jaws, mucous membranes of oral cavity, pharynx, larynx, and middle ear.
linings of pharyngeal arches
What are branchiomotor nerves?
motor fibers that supply muscles derived from pharyngeal (branchial) arches
The _________ innervates Arch 1.
Trigeminal nerve
The ________ innervates Arch 2.
Facial nerve
The _________ innervates arch 3.
Glossopharyngeal nerve
The __________ innervates arch 4/6
Vagus nerve
The head somites are (similar/different) in comparison to spinal somites.
similar just less developed
What are pretramatic nerves?
sensory branches of branchial arches that are out of their arch territory.
Pretramtic nerves provide what type of innervation? (sensory, motor, or mixed)
Sensory
Pretrematic nerves provide innervation to the area ________ to its arch.
cranial
Ophthalmic division of the trigeminal nerve, Chorda Tympani, and tympanic branch are __________
pretrematic nerves
The tympanic branch stems from which cranial nerve?
Glossopharyngeal nerve
The tympanic branch travels from ______ to ______ to provide _______ neurons
arch 3, middle ear, visceral sensory
Chorda Tympani travels from ______ to ______ to provide ______.
arch 2, stomodeum/oral cavity, taste to anterior 2/3 or tongue
Ophthalmic nerve travels from _____ to _____ to provide ______ to orbit and upper face.
arch 1, areas around optic cup, general sensory neurons
The endoderm receives ( visceral or general) sensory innervation?
visceral
What type of sensory innervation do oral and nasal cavities receive and why?
general sensory innervation because arch 1 has ectoderm on its outside and inside from the lining of the stomodeum
What structures does the foregut give rise to?
pharynx, larynx, trachea, and thyroid gland
______ are endodermal extensions of the pharynx between branchial arches..
Pharyngeal pouches
Whats structures do pharyngeal pouches give rise to
palatine tonsils
middle ear
thymus
parathyroid glands
Endoderm ______ the foregut.
lines
What is the beginning of the foregut?
posterior 1/3 of tongue
The posterior 1/3 of our tongue is the _________ of the oral pharynx.
anterior wall
Which pharyngeal arches flank the foregut?
Arches 2-6
The ________ and _________ flank the stomodeum
fronto-nasal process
maxillary and mandibular parts of arch 1
What is the fronto-nasal process composed of?
surface ectoderm of forebrain
What structures does the frontonasal process form?
forehead, nose, part of the upper lip
On day _____ the olfactory placode beings invaginating and the lens of the eye begins sinking underneath.
31
First branchial groove of ectoderm lines the _________.
external auditory meatus down to the ear drum and ear cartilages
At _______ embryo starting to have more of a human face
10-14 weeks
Which nerves are associated with the branchial arches?
V, VII, IX, X
Which cranial nerves only provide somatomotor innervation?
Occulomotor (III), Trochlear (IV), Abducens (VI), Hypoglossal (IX), Acessory (XI)
Which cranial nerves only provide special sensory innervation?
Olfactory (I), Optic (II), Vestibulocochlear (VIII)
Which cranial nerves provide mixed (both motor and sensory) innervation
Trigeminal (V), Facial (VII), Glossopharyngeal (IX), Vagus (X)
Head somites consist of _______ and ________.
preotic somites, postotic somites
Somatic mesoderm gives rise to ________ and is innervated by ________.
neck muscles, accessory nerve
The optic cup is part of the ________.
neural tube
What are the derivatives of the ectoderm?
Neural tube
Surface covering of head and neck (including stomodeum and branchial grooves)
Sensory innervation of head
Placodes (olfactory, lens, otic)
What structures does the optic cup give rise to?
retina
optic nerve (II)
What structures does the otic placode give rise to?
Inner ear (cochlea/semicircular canals)
How does the eye develop?
lens placode (thickened ectoderm) sinks under the surface as a lens pit
It becomes a lens vesicle (hollow ball) that will pinch off
lens vesicle is surrounded by optic cup
head mesenchyme from neural crest cells condenses around optic cup to form the connective tissue elements of the eye
The ______ is the thin layer of skin covering our ear canal.
external acoustic meatus
How does the ear develop?
Otic placode sinks under surface and forms otocyst
Otocyst pinches off from surface ectoderm and shapes itself into the cochlea and semicircular canals
Arch 1 and Arch 2 cartilages form the middle ear bones
First pharyngeal pouch forms middle ear
First branchial groove (on outside) forms external auditory meatus
Does the otic placode become our external ear?
NO it sinks under, similar to the lens placode
The first pharyngeal pouch forms the ________.
middle ear cavity
Pharyngeal arches originate from ______ and _______
somites, head mesenchyme
What structures does a pharyngeal arch contain
Cranial nerve
artery
mesenchyme
piece of cartilage
There is a _________ between pharyngeal groove and pharyngeal pouch.
Pharyngeal membrane
What clinical complication can occur due to a break down of pharyngeal membrane during embryonic development?
pharyngeal fistula connecting air on outside to lumen of the pharynx
Arch 1 forms _____ and _____
malleus, incus
Arch 2 forms _______, _______, _______, _______.
stapes, styloid process (of temporal bone), lesser Cornu of hyoid bone
Arch 3 forms _______ and _______.
greater Cornu of hyoid, body of hyoid
Arches 4/6 form ______ and ______.
thyroid cartilage, cricoid cartilage
The ______ is the adam’s apple.
plate of thyroid cartilage
Cartilages from arch 4/6 stay as ________ cartilage in their adult derivatives.
hyaline
How far do the branchial cartilages go?
larynx
Muscles of mastication derive from ______.
Arch 1
Muscles of facial expression derive from _______.
Arch 2
Through what method of ossification does the mandible develop?
intramembranous ossification
How does intramembranous ossification occur?
head mesenchyme cells begin differentiating into osteoblasts to deposit bone matrix
NO cartilaginous precursor
The former site of 1st arch cartilage serves as a _________ for condensation head mesenchyme around it to form membrane bone of mandible.
organizing center
What is special about arch 2 mesoderm?
It migrates out of its territory to form face muscles
Muscles of the larynx and pharynx develop from ______.
Arch 4/6
Pharyngeal constrictor muscles are the first layer of muscle of the ________.
GI tract
________ is the ONLY origin for all sympathetic neurons.
Thoracolumbar outflow (T1-L2)
How do sympathetic fibers get to the head?
Exit spinal cord and ascend upward to the sympathetic trunk, synapse onto one of three cervical ganglia, travel to the head
Cranial nerves do not have _________ outflow at its origin in the brain.
sympathetic
How do post sympathetic synaptics of the inferior cervical ganglion get to the head?
Hop onto the vertebral artery
Post sympathetic synaptics of the middle cervical ganglion hop on the ________ to get to the head.
external carotid artery
Post sympathetics of superior cervical ganglion hop on the ______ to get to the head.
internal carotid artery
Smooth muscle of arterial walls is a target of ________.
sympathetics
makes sense the postsynaptic sympathetics hop onto the arteries
How do parasympathetics get to the head?
Parasympathetic presynaptics leave the brain with cranial nerves
Which 4 cranial nerves provide parasympathetic innervation?
Oculomotor (III)
Facial (VII)
Glossopharyngeal (IX)
Vagus (X)
Parasympathetic presynaptics synapse in _______ and join the branches of the _______ nerve to their targets.
ganglion, trigeminal
Path of parasympathetics to the eyeball
Presynaptic parasympathetics leave the brain with the oculomotor nerve
They synapse onto the ciliary ganglion
Postsynaptics travel with short ciliary nerves to their target
The oculomotor nerve past the ciliary ganglion is only ______.
somatomotor
