Oral Cavity, Pharynx and Salivary Glands Flashcards
What is the roof, floor and lateral walls of the oral cavity?
– Roof: hard & soft palates
– Floor: mainly soft tissues,
including tongue
– Lateral walls: cheeks
Where is the oral cavity?
Sits below the nasal cavity
What seperates the oral cavity and into what?
The dental arches separate the oral cavity into the oral vestibule & oral cavity proper
What is anterior and posterior to the oral cavity?
- Anteriorly is the opening of the oral cavity, the oral fissure, created by the lips
- Posteriorly is the oropharynx
What structures are at the back of the oral cavity and what is between them?
Palatoglossal & palatopharyngeal, of the soft palate, form arches (aka anterior & posterior pillars of the fauces [space between oral cavity & pharynx] respectively) with palatine tonsils between these
What is the function of the oral cavity?
- Take in food & fluid
- Add saliva & start digestion
- Chew & swallow
- Taste
- Protection (tonsils: mainly in the pharynx)
What are the two divisions of the oral cavity?
Oral cavity (proper): Space between the teeth
Oral vestibule: Space between the lips/cheeks & dental arches (teeth)
What are the main features of the oral vestibule?
labial frenulum (upper/lower): a mucosal fold that connects the gingiva to the lips in the midline
buccal frenulum: mucosal folds that are lateral
What is the lining of the lips and cheeks externally/internally?
histologically
externally: skin
internally: non-keratinised stratified squamous epithelium lining the mucous membrane
What is the main muscular component of the cheeks?
buccinator
compresses the oral vestibule and aids chewing
What are the features of the lips?
what are they?
philtrum - depression in midline above upper lip and is a vestigal feature
oral fissure - opening between the lips
orbiculairs oris - main component of lips acting as a sphincter for the oral fissure
What acts as a schincter for the oral fissure?
what assists in altering the shape and size?
orbicularis oris
buccinator is involved in altering shape and size
What is the hard palate formed by?
Anterior 3⁄4 formed by palatine process of maxilla
Posterior 1⁄4 by the horizontal process of palatine bones & overlying mucosa
What does the mucosa of the hard palate have and what does it do?
palatine rugae thought to help tongue with movement of food; they are unique to an individual
What is anterior to the rugae?
incisive papilla which overlies the incisive fossa
What passes through the incisive canals?
nasopalatine nerve
greater palatine artery
What is the soft palate and what is it’s role?
Muscular continuation of hard palate that acts to close the oropharyngeal isthmus or separate the oro- & naso- pharynx
What are the muscles of the palate?
musculus uvaulae
palatopharyngeus
tensor veli palatini
levator veli palatini
What nerves supply the palate muscles?
by the vagus nerve (CN V) except for the tensor veli palatini which is supplied by the mandibular nerve (CN V3)
What is the blood supply of the palate?
- Greater & lesser palatine artery (ECC > maxillary artery > descending palatine)
- Greater palatine supplies the hard palate
- Lesser palatine supplies the soft palate
What nerves provide general sensation to palate?
nasopalatine - hard palate
greater palatine - hard palate
lesser paalatine - soft palate
all v2 branches
What divides the tongue and into what?
the terminal sulcus divides the tongue into an anterior 2/3rd (oral) and a posterior 1/3rd (pharyngeal)
What covers the external surface of the tongue?
papillae (fungiform, foliate, vallate, filiform) to grip food & house taste buds (except filiform which is for texture)
What is the midline of the inferior surface of the tongue marked by?
frenulum of the tongue which extends from the inferior
surface of the tongue, along the midline, & is continuous with the mucosa of the
floor of the mouth
What can be seen on each side of the frenulum?
lingual vein
sublingual folds
What do extrinsic tongue muscles do?
alter position
What do intrinsic tongue muscles do?
alter shape
What are the extrinsic muscles of the tongue and what do they each do?
genioglossus - protrudes tongue
hyoglossus - depresses the sides of the tongue
styloglossus - elevates and retracts
palatoglossus - elevates posterior tongue
Where does the lingual artery enter the tongue?
enters the tongue between the hyoglossus and genioglossus muscles
Where do the hypoglossal and lingual nerves enter the tongue?
external surface of the hyoglossus
Where does the lingual nerve travel and what with?
travels together with chorda tympani to anterior 2/3rd of tongue
What is the motor supply of the tongue muscles?
Motor supply to all tongue muscles is by the hypoglossal nerve (CN XII) except for palatoglossus that is supplied by the vagus nerve (CN X)
What is general/special sensation of the anterior 2/3rd (oral) supplied by?
- General sensation via mandibular division (CN V3) of trigeminal nerve (CN V) - Lingual
- Taste via facial nerve (CN VII) - Chorda Tympani
What is general/special sensation of the posterior 1/3rd (pharyngeal) supplied by?
- General sensation & taste via glossopharyngeal nerve (CN IX)
What is the blood supply and venous drainage of the tongue?
- The lingual artery is the major arterial supply to the tongue (from ECC)
- The deep lingual & dorsal lingual veins drain the tongue (both drain into the IJV)
What are the parts of the pharynx?
- The nasal cavity (nasopharynx)
- The oral cavity (oropharynx) that is a common pathway for air as well as food & fluid
- The larynx (laryngopharynx)
What are tonsils?
what is their name
lymphoid tissue - found in several places forming walderyers tonsillar ring
What are the 4 tonsils?
- Pharyngeal tonsils (“adenoids”),
nasopharynx - Tubal tonsils (around tympanic tube opening), nasopharynx
- Palatine tonsils (“tonsils”), fauces/oropharynx
- Lingual tonsils, posterior third of tongue
What holds the nasopharynx open?
pharynogobasilar fascia
What are the muscles of the pharynx?
- 3 pharyngeal constrictors (superior, middle & inferior) pushing the food bolus towards the oesophagus
- Pharyngeal elevators lifting the pharynx to receive the food bolus from the oral cavity
What are nerves that can be seen coming out the cranial base on the posterior aspect of the pharynx?
what are they between?
CN IX, X, XI, XII
between the internal carotid artery and internal jugular vein
What are the pharngeal constrictors supplied by?
nerve
vagus via the pharyngeal plexus
What happens when the superior, middle and inferior constrictors contract sequentially?
they force food bolus towards the oesophagus
What structure does the inferior pharyngeal constrictor have and what is it’s role?
a lower circular part known as cricopharyngeus that forms a sphincter around the upper oesophagus preventing air being drawn into the stomach during inhalation
Where do pharyngeal elevators come from?
descend from the skull to fan out into the inner surface of the pharynx
Where do the pharyngela elevators also send fibres to?
Some may also send fibres to the thyroid cartilage ensuring simultaneous elevation of the pharynx & larynx during swallowing
What are the pharyngeal elevators?
palatopharyngeus
stylopharyngeus
salpingopharyngeus
What is the role of the palatopharyngeus and what nerve is it supplied by?
- Elevates the pharynx & larynx
- Also draws the soft palate
downwards - Supplied by the vagus nerve
(CN X)
Where does the stylopharyngeus originates, what is it’s role and what nerve is it supplied by?
- Originates from the styloid process
- Elevates the pharynx & larynx
- Only pharyngeal muscle supplied
by the glossopharyngeal nerve (CN IX)
Where does the salpinogopharyngeus originate, what is it’s role and what nerve is it supplied by?
- Originates from the auditory tube
- Elevates the pharynx & larynx
- Also helps open the auditory
tube during swallowing for pressure equalisation in the middle ear - Supplied by the vagus nerve (CN X)
What plexus supplies the pharynx and where is it?
the pharyngeal plexus that lies on the external pharyngeal wall (over middle constrictor) & receives branches of CN IX & X as well as cervical sympathetics
What is parasympathetic secretomotor of the pharnyx by?
by CN X directly & pterygopalatine ganglion (CN VII) via CN V2
What nerves are involved with the gag reflex?
Gag reflex afferent CN IX & efferent CN X
What is muscular motor innervation of the pharynx by?
Musculature by CN X except stylopharyngeus that is by CN IX
What is the nasopharynx sensation supplied by?
cnv2
What supplies sensation to Oropharynx, palatine tonsil, inferior aspect of soft palate & posterior 1/3 of tongue?
CNIX
referred pain to middle ear
What supplies sensation to laryngopharynx, vallecula & epiglottis?
CNX
What supplies sensation to soft palate?
combination of CN V2 (anterior part) & CN IX (posterior part)
What are the functions of salivary glands?
Secrete saliva to:
* Begin digestion of starches
* Keep mouth moist
* Lubricate food
* (Help) prevent tooth decay
* Control bacterial flora of oral
cavity
What type of secretion does each gland have?
parotid - serous
submandibular - serous and mucous
sublingual - serous and mucous
What are the 3 types of salivary secretions?
what is their composition
- Serous (amylase, lysozyme) – protein secreting
- Mucous (sialomucins) – mucin secreting
- Mixed (serous secretion and sialomucins)
Where is the submandibular gland?
Found along mandible, partly superficial (below) & partly deep (above) to the mylohyoid (free posterior border of muscle) – the gland wraps around the mylohyoid Deep part lies in the floor of the oral cavity, lateral to the root of the tongue
What loops under submandibular duct before it opens in oral cavity?
lingual nerve
Where do the submandibular ducts begin?
in gland between mylohyoid & hyoglossus
What does the submandibular gland have surrounding it?
Has a fascial capsule covering the gland that is continuous with the deep investing cervical fascia
What are the anatomical relations of the submandibular gland?
Digastric muscle (anterior belly)
Facial artery
Mylohyoid muscle
Hypoglossal nerve
What is the blood supply/venous drainage of the submandibular ducts?
via submental arteries (branch of facial)
via submental veins (to lingual and facial)
Where do submandibular ducts open?
3 orifices in the oral cavity besides the base of the frenulum (small sublingual papilla/caruncles)
Where is the sublingual gland?
Almond-shaped, lies in the floor of the mouth between the mandible & hyoglossus, lateral to the submandibular duct & lingual nerve (CN V3)
Sits in sublingual fossa of mandible, superior to anterior part of the mylohyoid line
Where do sublingual ducts open?
numerous & drain into the oral cavity via openings into crest of the sublingual fold (can sometimes empty with the submandibular duct at sublingual papilla/caruncles)
What is the blood supply/venous drainage of the sublingual ducts?
Blood supply is via submental & sublingual arteries (branch of facial & lingual arteries)
Venous drainage is via submental veins (to lingual & facial veins) (similar to submandibular)
What are the anatomical relations of the sublingual gland?
Lingual nerve
Hypoglossal nerve
What is the parasympathetic innervation path of the sublingual/mandibular gland?
- Preganglionic parasympathetic fibres travel to the submandibular ganglion from the chorda tympani (CN VII nervus intermedius) & via the lingual nerve (CN V3)
- Postganglionic parasympathetic fibres then travel in the lingual nerve (CN V3) to the sublingual gland OR travel directly to the sublingual & submandibular glands not in a nerve
What is the sympathetic innervation of the sublingual/mandibular gland?
Sympathetic innervation is derived from the superior cervical ganglia & the nerve plexus on the external carotid artery resulting mainly in vasoconstriction & reduction in volume of saliva that leads to dry mouth
Where are the minor salivary glands and what are they?
what is their innervation
Minor salivary glands are found diffusely embedded throughout the submucosa of the oral cavity:
* Buccal (cheek)
* Palatine (palate)
* Lingual (tongue)
* Labial (lip)
Innervated by CN VII & CN V
What are minor salivary glands susceptible to?
mucoceles (swelling due to blockage of associated ducts)
What is the parasympathetic path of minor salivary glands above oral fissue?
- Preganglionic parasympathetic fibres travel to the pterygopalatine ganglion in thegreater petrosal nerve (CN VII nervus intermedius)
- Postganglionic fibres travel to the palate via the palatine nerves
What is the parasympathetic path of minor salivary glands below oral fissue?
- Preganglionic parasympathetic fibres travel to the submandibular ganglion from the chorda tympani (CN VII nervus intermedius) & via the lingual nerve (CN V ) 3
- Postganglionic parasympathetic fibres then travel in the lingual nerve (CN V3) to the glands OR travel directly to the glands not in a nerve
What are the pathologies of salivary glands or ducts?
3
mumps
salivary stones/calculi (sialolithiasis)
excessive salivation (ptyalism)
