Anatomy of the oral cavity- glands, tongue, swallowing Flashcards
Where does the oral cavity span from anteriorly–> posteriorly?
the oral cavity can be divided into 2 parts. what divides it and which 2 sections does this create?
anterior border of the oral cavity: oral fissure (opening between the lips)
posterior border of the oral cavity: oropharyngheal isthmus (opening of the oropharynx)
oral cavity is split into 2 parts divided by the upper and lower dental arches into the vestibule and mouth proper
what is the vestibule of the mouth?
how does it communicate with the mouth proper?
the duct of which gland empties into the veticule behind upper molar 2?
- the vestibule of the mouth is the space between the lips/ cheeks and the gums/teeth
- communicates with mouth proper by gaps behind molar no*3
- duct of parotid gland empties out into the vesticule secreting salivary juices
what are the broders of the mouth proper?
roof-
lateral walls-
floor-
roof- hard and soft palates
lateral walls- cheeks
floor- muscular diaphragm, geniohyoid muscles, tongue, salivary gland and duct
Roof-
- what 2 structures make up the palate?
- what epithelium covers the hard palate?
- what is the soft palate made of/
- what is the function of the soft palate?
- the hard and soft palate
The hard palate
- the hard palate is found anteriorly and it seperates the oral and nasal cavities
- the hard palate is covered by respiratory mucosa (ciliated pseudostratified columnar epithelium) superiorly and by oral mucosa inferiorly (stratified squamous epithelium)
the soft palate
- continuation of the hard palate
- muscular structure
- acts as a valve to:
- lower and therefore clsoe the oropharyngheal isthmus (this prevents the food bolus from entering the nasopharynx)
- elevate and seperate the nasopharynx from oropharynx
Cheeks- lateral wall
which msucle forms this?
what is the cheek lined by?
which nerve innervates the cheek?
buccinator muscle forms the wall
lined by oral mucosa (stratified squamous non-keritinsied)
innervated by buccal branches of the facial nerve
What makes up the floor of the oral cavity
- muscular diaphragm- comprised of bilateral mylohyoid muscles. this structure pulls the larynx forward during swallowing.
- geniohyoid muscles- pulls larynx forward during swallowing
- tongue- connected to the floor by the frenulum
- salivary glands + ducts
Sensory innervation of the oral cavity
largely via 2 nerves
- hard palate
- soft palate
- cavity floor
- tongue
- cheeks
- hard palate- greater palatine nerve and nasopalatine nerve (both branches of the V2)
- soft palate- lesser palatine nerve (branch of V2)
- cavity floor- lingual nerve (branch of V3)
- Tongue- special sensory fibres for taste via chorda tympani (branch of facial nerve)
- Cheeks- buccal nerve (branch of facial nerve
The tongue contains 8 muscles
how are they divided
by whether theyre intrinsic (4) or extrinsic (4)
intrinsic tongue muscles
- what makes them intrinsic?
- name correlates to their direction of travel- what are their names?
- overall what do they do to the tongue?
- what does each do to the tongue?
- motor innervation to them is via?
intrinsic tongue muscles only attach to other tongue muscles
with all 4 of them, their name correlates to their direction of travel:
- superior longitudinal- shorten tongue
- vertical- shorten tongue
- transverse- flatten tongue
- inferior longitudinal- flatten tongue
The above is their layout within the tongue
overall thay change the shape+size of the tongue
motor innervation is via the hypoglossal nerve
what are the 4 extrinsic tongue muscles
- where do they attach
- where do they insert
- what is their functions
- what is their innervation
Genioglossus
- function: inf fibres- protrude the tongue/// middle fibres- depress the tongue/// superior fibres- tip back and down
- innervation: motor via the hypoglossal nerve
- attach: mandibular symphysis and inserts: into the body of the hyoid bone
Hypoglossus
- function: depresses and retracts the tongue
- innervation- hypoglossal nerve
- attach: hyoid bone, inserts: side of the tongue
Styloglossus
function- retracts and elevates the tongue
innervation- hypoglossal nerve
attach: styloid process of the temporal bone insert: side of the tongue
Palatoglossus
function- elevates posterior part of the tongue closing the oropharyngeal isthmus
innervation- vagus nerve
attach-*** palatine aponeurosis ***insert- broadly across the tongue
name the 4 muscles
yellow- geniohyoidus
blue- genioglossus
green- hyoglossus
purple- styloglossus
innervation to the tongue
- general sensation anterior 2/3
- taste anterior 2/3
- general sensation posterior 1/3
- taste posterior 1/3
- what is the arterial and venous supply to the tongue
- lymphatics of the anterior 2/3 and posterior 1/3
damage to the hypoglossal nerve
LMN lesion (damage to nerve itself)- curve towards the damaged side when protruding
(((((UMN lesion (damage to nerve pathway)- curve away due to action of genioglossus???)))))))
arterial supply to the tongue- lingual artery (majority) + tonsillar artery (both branches of ECA)
drainage- lingual vein
The hard palate is composed of which 2 bony parts
hard palate contains (3) foramina/ canals
2 arches bind the soft palate:
what sits between these 2 arches
hard palate- palatine processes of the maxilla + horizontal plates of the palatine bones
- incisive canal- transmits the nasopalatine nerve
- greater palatine foramen- greater palatine nerve and vessels
- lesser palatine foramina- lesser palatine nerve
palatoglossal arches anteriorly and the palatopharyngeal arches posteriorly
between these 2 arches sits the palatine tonsils
5 muscles make up the soft palate
they are all innervated by? apart from x which is innervated by?
what are the 5 muscles that make up the soft palate and their functions and attachments
all innervated by the pharyngeal branch of the vagus nerve
apart from tensor veli palatini which is innervated by the medial pterygoid branch of V3
1) tensor veli palatini
- function: tenses soft palate
- attachments: origin- medial pterygoid plate of the sphenoid bone insertion: palatine aponeurosis
2) levator veli palatini
- function: elevation of the soft palate
- attachments: attach- petrous temporal bone + eustachian tube insert- palatine aponeurosis
3) palatoglossus
- function: pulls soft palate towards tongue
- atatchments: palatine aponeurosis. insert: side of the tongue
4) palatopharyngeus
- function: tenses the soft palate, drawing the pharynx anteriorly when swallowing
- attachments: poaterioer nasal spine and palatine aponeurosis to thyroid cartilage
5) muscularis uvulae
- function: shortens uvula
- attachments: post nasal spine and aponeurosis to the uvula
innervation of the soft palate
general sensory- maxillary branch of the trigeminal
glands of the hard palate- greater palatine nerve
mucous membrane of the ant. hard palate- nasopalatine
soft palate- lesser palatine
what is a cleft?
what is a cleft lip?
what is a cleft palate?
complications
a cleft refers to a gap/ split in the upper lip or the palate. it results from a defect during developemnt of the face and palate.
cleft lip- occurs when the medial nasal prominence and maxillary prominence fail to fuse.
celft palate- can occur in isolation when the palatal shelves fail to fuse in the midline, or in combination with cleft lip.
complications
- psychological and societal
- death if baby is unable to feed
- recurrent ear infections and speech impediment
label the anatomy of the parotid gland
yellow- parotid gland
pink- zygomatic arch- superior border
light blue- sternocleidomastoid- posterior border
red- masseter
green- buccinator
how many parotid glands are there
what kind of gland is it
what does it secrete
what is its anatomical structure
bilateral so 2 parotid glands
salivary gland
it secretes serous saliva
lobular and irregular morphology- deep and superficial lobe seperated by the fsacial nerve
the parotid gland lies within the parotid region (deep hollow)
what are the boundaries of it?
- superior
- inferior
- anterior
- posterior
superior- zygomatic arch
inferior- inf border of the mandible
anterior- massester muscle
posterior- external ear and sternocleidomastoid
what is the anatomical course of the parotid gland
- secretion are via the Stenson duct
- it arises on the anterior part of the gland
- traverses the masseter muscle
- moves medially
- pierces buccinator
- opens into the oral cavity near molar 2
What are the anatomical relationships of the parotid gland?
why are they important to learn?
- facial nerve- gives rise to its 5 terminal branches in the parotid gland- facial expression
- External carotid artery- ascends within the parotid where it gives rise to the terminal branches: posterior auricalar, maxillary and superficial temporal arteries
- Retromandibular vein- formed here from the superficial temporal and maxillary veins
important as they can be severed during parotid gland surgery
explain the
- arterial supply
- venous supply
- sensory innervation
- autonomic parasympathetic
- autonomic sympathetic
of the parotid gland
- arterial supply- posterior auricular and superficial temporal bracnhes of the ECA
- venous supply- retromandibular vein
- sensory innervation - auriculotemporal nerve (gland) and the great auricular nerve (fascia)
- autonomic parasympathetic - glossopharyngeal nerve –> otic ganglion–> auriculotemporal nerve to parotid causing increase saliva secretion
- autonomic sympathetic- originates in the superior cervical ganglion (part of the paravertebral chain) –> fibres travel along the ECA–> parotid inhibiting secretion via vasocontriction
Sublingual glands
- where are they found
- what kind of gland are they
- which nerves pass alongside the medial aspect
- how many sublingual glands are there? what is the name of the structure that they unite to form?
sublingual glands
- found in the sublingual fossa underneath the tongue, bordered by mylohyoid and masseter
- mostly mucous gland in nature
- submandibular and lingual nerves pass alongside the medial aspect of the glands
- there are 2 sublingual glands, they unite to form a horseshoe shape known as the the lingual frenulum
What is the course of the sublingual gland?
what is the anatomical variance in some people?
- secretions drain into the oral cavity by the minor sublingual ducts (of Rivinus), exits via the submandivular papilla
- in some the secretions drain into a major sublingual duct (of Bartholi)
sublingual
what supplies x to the sublingual glands?
- arterial
- venous
- parasympathetic
- sympathetic
sublingual gland
- arterial- sublingual and submental arteries (both fed by the facial artery)
- venous- sublingual (ligual- Int. Jug.) + submental (facial- int. jug)
- parasympathetic- superior salivatory nucleus via chorda tympani–. chord tymp. unifies with the lingual branch of V3–> synapse at submandibular ganglion–> post synaptic innervation drives effect
- sympathetic- superior cervical ganglion–> post synaptic vasoconstrictive fibres travel as plexus on the int. ext. carotid arteries –> facial, submental and sublingual arteries
submandibular glands
- what do they secrete
- located in which part of the submandibular triangle? what are the boundaries of the submandibular triangle?
- made up of 2 arms, what determines which arm is which?
secrete a mix of serous and mucous saliva
located in the anterior portion of the submandibular triangle
boundaries of the submandibular triangle
- superior- inf border of mandible
- anterior- ant. belly of digastric
- posterior- post belly of digastric
made of 2 arms, differentiated by their relation to mylohyoid that they wrap around
- superficial arm- sits in the submandibular fossa
- deep arm- hooks around posterior aspect of mylohyoid
what is the anatomical course of the submandibular gland
- travels into the oral cavity via the submandibular duct (Wharton’s duct)
- emerges from the deep arm between mylohyoid, hypoglossus and genioglossus
- duct enters into 1/3 orifices on a sublingual papilla bilaterally at the base of the lingual frenulum
both the submandibular duct and gland share intimate relations with 3 nreves, what are they?
explain these relations
submandibular duct and gland has intimate relations with:
- lingual nerve
- hypoglossal nerve
- facial nerve
lingual nerve- begins at the submandibular duct, goes anteromedially to loop beneath the duct before branching, branches ascend over hypoglossus to provide somatic info to anterior 2/3 of the tongue
hypoglossal nerve- lies deep to the submandibular gland + runs superficial to hypoglossus + deep to digastric
facial nerve (marginal mandibular branch)- exits anterior inferior part od the parotid gland at the nagle of the jaw and curves down inferior to the submandibular gland.
what is the vasculature to the submandibular gland?
arterial?
venous?
innervation? para and symp
submandibular gland
arterial- submental (facial) and sublingual (lingual)
venous- facial (into IJV) + sublingual (lingual ->IJV)
innervation
para
- presynaptic fibres via the chorda tympani
- superior salivatory nucleus
- chorda tymp unifies with the lingual branch of the mandibular nerve
- syanpse at the submandibular ganglion
symp
superior cervical ganglion
postsynaptic vasoconstrctive firbes travel down branches of the ECA (facial, sublingual and submental)
The pshyiology of swallowing can be split into 3 distinct sections.
name and explain them.
-
Voluntary phase
- mastication leads to a bolus of food being produced
- back of tongue elevates
- soft palate pulled anteriorly against it (keeps food in cavity allowing airway to be open)
- inspiration inhibited
- bolus moved to pharynx by tongue
- stimulation of swallowing reflex
-
Pharyngeal phase
- bolus moved to pharynx
- pressure receptors activated in the palate and anterior pharynx
- signals the swallowing centre which:
- inhibits respiration
- raises the larynx (helps block off access to the trachea?)
- closes the glottis (prevents bolus entering resp system)
- opens the upper oesophageal sphincter
- soft palate raises to clsoe the nasopharynx, allowing the passage of food
- true vocal cords close to prevent aspiration
- bolus moved to the oesophagus via peristalsis and pharyngeal constrictor muscles
- Oesophageal phase
upper 1/3 of oesophagus is voluntary skeletal muscle and the lower 2/3 is involuntary smooth
- larynx lowers returning to its normal position
- cricopharyngeus contracts to prevent reflux+respiration begins
