9. Anatomy of oral cavity Flashcards
where does the oral cavity lie?
inferior to the nasal cavity
what does the oral cavity consist of?
2 lateral walls, a floor and a roof
what forms the lateral walls of the oral cavity?
buccinators (cheek muscle)
what do the buccinators act with and what are their function?
buccinators act with tongue to keep food between teeth when chewing
what forms the roof of the oral cavity?
hard and soft palate
what forms the floor of the oral cavity?
muscular diaphragm and the tongue
with other soft tissues
where does the oral cavity begin anteriorly?
oral fissure (bounded by the lips)
where does the oral cavity extend posteriorly?
to the oropharyngeal isthmus
connection between oral cavity and pharynx
what is the isthmus?
an ‘arch’ formed by the soft palate above
and the upper surface of the tongue below
what forms the sides of the oropharyngeal isthmus?
anterior and posterior pillars of the fauces
what forms the pillars / arches (of fauces)?
palatoglossal muscle (anterior) palatopharyngeal muscle (posterior)
where do the palatoglossal and palatopharyngeal muscles run from?
from the soft palate of the tongue and pharynx
when do the palatoglossal and palatopharyngeal muscles contract?
contract during chewing to pull the soft palate down towards the back of tongue, closing the oropharyngeal isthmus
why do the palatoglossal and palatopharyngeal muscles contract?
ensure the food remains in the oral cavity while chewing
what lies between the pillars (of fauces)?
tonsillar fossa
what is within the tonsillar fossa?
palatine tonsil
one of annularly arranged lymphoid tissues of Waldeyer’s ring
when are palatine tonsils seen?
often easily visible and readily noticed when swollen due to inflammation e.g. tonsillitis
what does the oropharyngeal isthmus continue posterior into?
the oropharynx
what does the oral cavity plan an important role in?
function of the digestive system
function of oral cavity in digestive system?
entry of food to digestive tract
mastication –> bolus ready for swallow
what is digestive function of oral cavity aided by?
salivary gland secretions, lubricate food
contains enzymes to start chemical digestion e.g. amylase
what are the salivary glands?
parotid
submandibular
sublingual
what can form in ducts draining salivary glands? leading to?
stones can form in ducts draining the glands, causing significant pain and swelling in the salivary glands
(symptoms fluctuate in relation to eating)
which salivary gland is most commonly affected by having ducts draining it blocked?
submandibular gland
what type of tissue is the tongue and what is it covered entirely by?
an entirely muscular tissue covered in mucous membrane
what is the tongue capable of?
different shapes, positions and movements
what are the muscles creating the tongue classified into?
intrinsic and extrinsic
how many intrinsic muscles are there lying entirely within the tongue?
4 intrinsic muscles
run longitudinally, vertically, transversely
what are the intrinsic muscles of the tongue named according to?
the direction in which they travel and act to alter the shape of the tongue
what are the intrinsic muscles of the tongue attached to?
not attached to any bones, but blend in with the extrinsic muscles
how many extrinsic muscles are there? function?
4 extrinsic muscles, act to:
- change the position of the tongue
- anchor it to the surrounding structures
which structures do the extrinsic muscles of the tongue anchor the tongue to?
below: hyoid bone and mandible
above: styloid process and soft palate
what are all the muscles of the tongue innervated by?
the hypoglossal nerve (CN XII)
EXCEPT palatoglossus
which nerve innervates the palatoglossus muscle of the tongue?
CN X (vagus)
where does the tongue receive innervation from?
receives afferent innervation from a number of cranial nerves
why does the tongue receive its afferent innervation from a number of cranial nerves?
because of its embryological origins
pharyngeal arch 1,3,4
