Download NasoOroLaryngopharynx Oral cavity and what`s important Dentition

NasoOroLaryngopharynx
Oral cavity and what’s important
Dentition – 2 – 1 – 2 – 3 , dentition pattern, neuroectoderm
Palate – hard – 3 bones make it up, intermaxillary process (from two medial nasal processes fuse
together) and the palatine shelves. What covers the bones? Mucosa, it secretes, oral cavity has to stay
wet at all times to work. What innervates the inferior surface of the palate? Greater palatine n.
(terminal branch of V2, which is purely sensory (GSA), but parasympathetics from CN VII (postparasymp)
and postsymp from carotid plexus) Blood supply? Greater palatine a. is a terminal branch of the
maxillary a. No mm involved w/ hard palate except using it as an attachment point.
Soft – covered w/ mucosa (needs parasympathetic innervation, from the lesser palatine n.,
brach of V2 w/ same fibers that the greater palatine carried). No true skeletal element, but the tensor
aponeurosis is the tendon that attaches two mm bellies (9 – mm attach to soft palate, 4 paired mm and
one unpaired: tensor veli palatini (2, innervated by CN V3, tenses the soft palate by wrapping around
the hook of the hamulus of the medial pterygoid plate), levator veli palatini (X, lifts the palate),
palatopharyngeus (X, longitudinal mm of the pharynx, elev and pos pharynx for deglutition and
phonation), palatoglossus (X, final mm we use when we swallow, lifts the posterior portion of the
tongue up pushing bolus), musculis uvuli (X, lifts and retracts the uvula so we don’t gag, IX supplies
sensory to the uvula for the gag reflex). You can take the tensor veli palatini off the hook of the hamulus
and you turn it into a levator.
Tongue – 5 CNs assoc w. the tongue, 2 have motor influence (palatoglossus by X, the rest of the mm are
innervated by XII), 8 pairs of mm here, 4 extrinsic pairs and 4 intrinsic pairs. Intrinsic pairs are
innervated by CN XII for motor and they change the shape of the tongue. He doesn’t care about the
intrinsic mm. 4 pairs of extrinsic mm, these mm move the tongue, major positional changes.
Genioglossus (CN XII, if XII is damaged, the tongue deviates towards the lesioned side) is one of the first
one used by kids to protrude, and the biggest; a unique mm, only anchored at one end, only has a
proximal attachment, the genial tubercles of the mandible. Geniohyoid attaches there too.
Hyoglossus (CN XII) – attaches to hyoid bone and the lateral surface of the posterior of the
tongue, retracts the entire tongue and depresses the posterior of the tongue.
Styloglossus (CN XII) – attaches to styloid process and inserts on lateral surface of the hyoglossus
mm and the posterior portion of the tongue. Action is to retract and elev the posterolateral portion of
the tongue. W/ hyoglossus they retract the tongue.
Palatoglossus (CN X) – attaches to lateral surface of soft palate and tensor aponeurosis of soft
palate. Inserts on posterolateral surface of the tongue, retracts the tongue some, but elevates the
tongue to help swallow mainly.
Innervation of the tongue – drew a tongue, ID median sulcus, terminal sulcus, and foramen
coecum, these lines give us borders of innervation changes. Anterior to terminal sulcus (anterior 2/3 of
tongue) is innervated V3 (lingual nerve, sensory), VII (chorda tympani, special sensory). Then drew
valleculae epiglottica, b/t that and the anterior 2/3 of tongue, general sensory is IX, taste is IX. Very
back of tongue, just after valleculae epiglottica is innervated by: GSA – X and taste X.
Deficit in any of these mm, know the actions so you can answer these questions. Styloglossus,
stylohyoid and stylopharyngeus attach to styloid process (all innervated differently).
Floor – Principle mm of the floor of the mouth is the mylohyoid. Attachment points for mylohyoid are
the hyoid and the mylohyoid line on the body of the mandible, innervated by nn to mylohyoid, branch of
inferior alveolar, branch of V3, principally a sensory nn, except for mm derived from 1st pharyngeal arch
which receive innervation from V3. Myloyhyoid elevates the floor of the mouth, closing it off for
swallowing
Geniohyoid found here too – innervated by C1, which also innervates the thyrohyoid. The
branch that goes to thyrohyoid continues as the ansa cervicalis. Geniohyoid doesn’t do much. If you
lose V3, can we still swallow? Yes
Blood supply – Drew the aorta w/ brachiocephalic trunk (RCC and RSC aa.) and LCC and LSC aa.
Common carotids split into the internal and external carotid aa. External carotid aa has the branches we
are concerned with. 1st branch is superior thyroid aa., the 2nd branch is the lingual aa, 3rd branch is the
facial aa. Blood supply to tongue comes off the lingual aa., passes medial to the hyoglossus, where it
branches to the dorsal lingual aa (posterior 1/3 of the tongue and the root), also a branch that goes to
anterior portion of the tongue, the deep lingual aa., and the last branch the sublingual aa. Goes to floor
of the mouth. Venous drainage parallels this, venous commitantes.
Pharynx – made up of three parts, depending on where they are located, naso, oro, and laryngo. Drew
out the borders and the pharynx. Mainly made up of mm. Five components to the pharynx: mucosa,
submucosa, pharyngobasilar fascia, muscular layer, and buccopharyngeal fascia (danger space
immediately behind that, goes from base of skull to aorta)
2 groups of mm that make up the pharynx: longitudinal (aka vertical) and constrictors (aka
circular). Longitudinal mm vertically position the pharynx, they all attach to the thyroid cartilage at the
bottom (posterior lamina to be specific). These lift and tilt the thyroid cartilage slightly forward.
Longitudinal mm are innervated by IX and X,
3 longitudinal mm: stylopharyngeus – originates at styloid process, innervated by IX
(sens/motor), derived from 3rd pharyngeal arch.
Palatopharyngeus – innervated by IX (sensory) and X (motor)
Salpingopharyngeus – innervated by IX (sensory) and X (motor)
Cosntrictor mm – superior, middle and inferior, motor innervation to all is by X, sensory
comes from IX. Pharyngeal plexus made up by IX and X. Constrictors squeeze peristaltically from top to
bottom overlapping, bottom overlaps the top. Anterior attachment for superior constrictors is the
pterygomandibular raphe of the buccinators, posterior attachment is the pharyngeal raphe and the
pharyngeal tubercle. Anterior attachment of middle constr mm is the cornua of the hyoid, posteriorly it
attaches to pharyngeal raphe. Anterior attachment of inferior constrictor is thyroid and cricoid cartilage,
posterior attachment is pharyngeal raphe.
Larynx – thyroid cricoid arytenoid cartilages are the important ones. Epiglottic might come into
play. CN X is the only nerve we are worried about, sensory and motor innervation, two branches:
superior laryngeal nerve (goes to larynx, 2 branches: external (motor innervation to cricothyroid mm,
only mm not innervated by recurrent laryngeal n, and internal (sensory)) and recurrent laryngeal n.
(sensory below the vocal fold and motor to all mm except cricothyroid m.); these two are divided by the
vocal fold. 4 joints here, 2 cricothyroid (tilts cricoid cart on thyroid cart, stretches/loosens vocal fold for
pitch and 2 cricoarytenoid joints ( 3 important parts to larynx:
Vocal ligament – know what it is
Vocalis mm
Thyroid cartilage
Cricoid cartilage
Arytenoid cartilage
4 things that make up the vocal fold? Mucosa, vocal
Lost it at this point, no more notes from this guy, this is recorded.
Embryology
Covering face and neck (pharyngeal arches and prominences) and some respiratory embryo
Face
5 swellings lead to the formation of the face, 4 of these swelling come from the first
pharyngeal arch. Mandibular swellings meet in the middle and fuse make the mandible. Just superior
to the mandibular swellings are the maxillary swellings. Maxillary swellings never meet. Maxillary
swelling make the maxilla and cheeks. The fifth swelling is the frontonasal prominence. The single most
important to develop an appropriate face? All of them, failure in any of them lead to problems.
Treacher Collins – first arch syn, deaf and underdeveloped mandible.
Drew picture of swellings. Point of fusion b/t mandibular swellings is the mandibular raphe.
Maxillary swelling grow, but don’t meet. Frontonasal prominence develop thickening of tissue on the
lateral portion (nasal placode, thickening of tissue) which envaginates, then it is the nasal pit. Once the
pit is developed we get a furrow in the midline which divides this into the lateral and medial nasal
processes. Medial nasal processes form the bridge of the nose and most of the ala of the nose. Lat
processes form the rest of the ala of the nose and the cheek.
Looking laterally at the nasal pits (one on each side), once the buccopharyngeal membrane
breaks down and on the anterior end is the oral canal and the other end is the foramen of Paulman. As
the pits envaginate medially and posteriorly they end up fusing together. Now there are two holes
leading to common open cavity. At the posterior of the cavity apoptosis occurs, leading downward until
fusion w/ the posterior cavity of the oral cavity is made, this opening is the primitive choana. The tissue
that was isolated during this process breaks down until only a wedge is left, the intermaxillary process.
As the maxillary folds grow medially they meet the intermaxillary process and they fuse together. Now
we have two lines of fusion on the upper lip, the philtrum (ectocerm overlying the maxillary swellings
and intermaxillary process). The primary palate is made when the maxillary folds fuse with the
intermaxillary process. We do not have a divided nasal cavity nor a complete palate yet, have to
continue. Need to grow and modify some structures.
Looking from front, we see our primary palate, oral cavity and nasal cavity posterior and
superior. How do we make two halves of a nasal cavity? Grow septal downward (cartilage and mucosa),
cartilage will mostly ossify. On the lateral sides we develop extensions of the palatine bone, the palatine
shelves. Do the palatine shelves grow directly to the midline? No, grow downward at 40 dg angle,
aiming at root of tongue, when they aare 2/3 of full size, the proliferate on the bottom side and
apoptose on the top side and they hinge up to a level position, the shelves grow into and fuse w/ the
primary palate on the sides of the primary palate and the two shelves fuse together posterior to the
primary palate. Failure of the intermaxillary process to fuse to the maxillary swellings is how we get
cleft lip (unilateral or bilateral). If the lines of fusion b/t the primary palate and the shelves fail, we have
cleft palate (uni or bilateral). Failure of line of fusion b/t palatine shelves is the worst of all (still a cleft
palate), wide open choana, cannot swallow, food goes into your nasal cavity.
Dermal bone makes the rest of the face and the eyes and ears.
Pharyngeal arches – remnants of the gills;
1/2/3/4/6, 5th pharyngeal arch structures don’t exist in humans; each arch contains an artery,
nerve, and muscles, and cartilage. What do we know about the arteries here? Don’t care. If arteries fail
to develop, we die.
1 – CN V, mm of mastication,, incus, malleus
2 – CN VII, mm of facial expression, stapes, styloid process, lesser cornua of the hyoid bone and
upper rim of hyoid
3 – CN IX, stylopharyngeus m. , lower rim of hyoid bone and greater cornua
4 – CN X (superior laryngeal), pharyngeal constrictors, cricothyroid m., laryngeal cartilage
6 – CN X (recurrent laryngeal), intrinsic mm of the larynx, laryngeal cartilages
Reviewed the arteries with these, but said we didn’t have to worry about them for the test. Be able to
tell him if we have a failure of neural crest migration into arch one, they can’t hear. The cartilages are
primarily derived from neural crest cells, saw them during 4th week of development. Be able to say what
arch deficits came from and what fiber type of motor innervation is involved. SVE is the type of fibers
that we see here. GSA w/ CN V for sensory info for the face.
Clefts
Only important one is the first cleft. First cleft, without first pharyngeal cleft we can’t stick our
keys in our ears, becomes the external auditory meatus. What happens to the other clefts? They get
overgrown by a proliferation of the 2nd arch, if they don’t fill in we get a lateral cervical sinus, which can
turn into a lateral cervical cyst fluid filled, cut it out. The cervical cyst can have an internal or external
fistula. If you have both the baby leaks. What does the region b/t the first and 2nd arch become?
Tympanic membrane.
Pouches
How many pouches important? All of them
1st pouch – tympanic cavity and the auditory tube
2nd pouch – palatine tonsils, envagination of tissue which fills in with lymphoid tissue, almost a
complete ring around, Waldeyer’s tonsilar ring
3rd pouch – inferior parathyroids and the thymus
4th pouch – superior parathyroids
5th pouch – Calcitonin producing C cells
Gotta make the tongue – arises from the floor of the arches, four of the arches contribute. 1st portion of
the tongue comes from the floor of the first arch, a distal tongue bud. From floor of 2nd arch, we form
the copula. From the floor of 3rd and 4th arches we form the hypopharyngeal eminence. CNs V, VII, IX,
and X are here. CNXII comes later when mm come in. Distal tongue bud develops into two lateral
lingual swellings which overgrow the distal tongue bud. They hypopharyngeal eminence overgrows the
copula. Most of the cells from the copula undergo apoptosis, leaving innervation from CN VII (chorda
tympani). The line of fusion b/t hypopharyngeal eminence and lateral lingual swellings is the … and the
line of fusion b/t the lateral swellings is the…
About the time the lateral lingual swellings and hypopharyngeal eminence fuse, we see the thyroid
gland come in.
Thyroid tissue, placode of endothermal tissue, migrates down the neck, can have ectopic thyroid tissue.
While the thyroid is migrating downward, the sup and inf parathyroid glands have to cross along the
way to find their final position.
Lungs
Buccopharyngeal membrane and an anal membrane when we develop w/ the gut tube
connecting them. We develop resp sys off the gut tube. In the anterior portion of the gut tube, we
develop a diverticulum which elongates and develops two swellings at the end, called bronchial buds
turning into left and right lungs. As it grows it splits and closes off and makes a connection to the
pharynx (laryngeal atticus), now that we have split we split again, we will split the right side into three
and the left one into two. Three lobes on right lung, two lobes on the left lung. Primary bronchus, then
secondary bronchi, then split to tertiary bronchi. 10 tertiary bronchopulmonary segments on the right
and 8 on the left. These continue to divide.
Before we have a major split, just an outpouching, but doesn’t look like resp tissue, we are in
the pseudoglandular. As we branch, we are now in canalicular phase. When we start seeing
pseudoalveoi and terminal sacs, we are in the terminal sac or saccular phase. Towards end of saccular
phase we can gas exchange, surfactant is produced now, but squamous epithelium is too thick across
the resp membrane so not good exchange yet. When the epithelial of the resp membrane starts to thin,
we are in alveolar stage (32 wks). Born at 26 wks, 10-15% chance of survival. Once in alveolar stage,
only have half the alveolar functioning needed, so we go in an incubator and get surfactant. Surfactant
produced in an embryonic lung, once it reaches a certain level, the baby spits some out, and Mom starts
to contract, baby ready to breath.