Tongue Week 4 FINISHED Flashcards
What is the location of the tongue? Where is it mostly at rest?
Part in the pharynx and part in the oral cavity, mostly at rest in the oral cavity
What is the function of the tongue?
- mastication
- taste
- deglutition
- articulation
- oral cleansing
MAIN FUNCTIONS
- forming words during speech
- pushing food into the pharynx when swallowing
What are the regions of the tongue? Where are each of these parts?
Root, body, apex, dorsal surface, inferior surface
Root (posterior 1/3 rd)
Body (anterior 2/3 rds )
Apex (pointed anterior tip)
What are the 2 surfaces of the tongue?
Curved dorsal surface
Inferior surface/ sublingual surface
What is the terminal sulcus?
A V shaped groove which divides the tongue into:
- an anterior part or oral part / presulcal and
- a posterior part or pharyngeal part/post sulcal
What is the depression in the midline of the tongue?
Midline groove or sulcus, and divides the tongue into the right and left
What is deep to the midline groove or sulcus?
A fibrous septum, the lingual septum, which further divides the tongue into right and left halves.
What are the most mobile parts of the tongue?
The apex and body
What is the tongue covered in and why?
It is covered in a rough mucous membrane because of the presence of small lingual papillae
What do the small lingual papillae on the tongue contain?
Some contain taste receptors, some contain other afferent sensory nerve endings
Where can taste receptors be found?
On the tongue as well as the epithelium covering the oral surface of the soft palate, the posterior wall of the oropharynx and the epiglottis
What structures are posterior to the terminal sulcus on the tongue?
There are no lingual papillae, but instead has lingual tonsils; underlying nodules of lingual lymphatic follicles. This gives the posterior part of the tongue a cobblestone like appearance
What is the inferior surface of the tongue also known as?
The lingual surface
What is the inferior surface of the tongue made of? What is the fold in this structure called?
A thin transparent mucous membrane. The fold in the middle of this mucous membrane is called the lingual frenulum.
What can you see on either side of the midline frenulum of the inferior surface of the tongue?
You can see the openings to the submandibular gland, located on the sublingual caruncle (a papillae)
Do the muscles of the tongue act in isolation?
No, this is an oversimplification
Generally what do the intrinsic muscles of the tongue do?
They alter the shape of the tongue
Generally, what do the extrinsic muscles of the tongue do?
They alter the position of the tongue
How many muscles are there in each half of the tongue
8
- 4 intrinsic
- 4 extrinsic
What is the nervous supply for the muscles of the tongue? Are there any exceptions?
They are all innervated by CN XII (hypoglossal nerve) EXCEPT palatoglossus muscles which is innervated by CN X
In terms of general sensation of touch and temperature (not special sensation) what is the innervation for the tongue?
The anterior 2/3 is innervated by the lingual nerve which is a branch of CN V (3)
The posterior 1/3 is innervated by the lingual nerve which is a branch of CN IX (glossopharyngeal)
What nerve supplies the sensation of taste for the anterior 2/3 of the tongue?
CN VII - The facial nerve via a branch called the chorda tympani nerve. This nerve supplies all taste to the anterior 2/3 except for one papillae
What nerve supplies the sensation of taste for the posterior 1/3 of the tongue?
CN IX - the glossopharyngeal nerve
What nerve supplies the sensation for the root of the tongue? What sensations does it supply?
CN X via a branch called the internal laryngeal. It supplies the sensations of taste as well as general sense
What are the basic 4 taste sensations and where is each of these general found on the tongue?
Sweetness - apex/tip
Saltiness - lateral margins
Sourness and bitterness - posterior part of the tongue
What is the arterial supply for the tongue?
The lingual artery which is a branch of the external carotid artery
What is the venous drainage of the tongue?
Lingual veins directly or indirectly drain to the internal jugular vein
What are the 4 routes of drainage of the tongue?
- superior deep cervical l.n.
- inferior deep cervical l.n
- submandibular l.n.
- submental l.n
Genioglossus OIAN
O - superior mental spine of the mandible
I – dorsum tongue, hyoid bone
Innervation - CN XII
Action – depress tongue, protrusion, unilaterally deviates tongue to the opposite side
Hyoglossus OIAN
O – hyoid bone
I – side, inferior tongue
Innervation - CN XII
Action – depress tongue, retraction
Styloglossus OIAN
O – styloid process, stylohyoid ligament
I – side, inferior tongue
Innervation - CN XII
Action – retracts the tongue
Palatoglossus OIAN
O – aponeurosis, soft palate
I – side of the tongue
Innervation - CN X, via pharyngeal plexus
Action – elevates posterior tongue
What are the extrinsic muscles of the tongue?
Genioglossus
Hyoglossus
Styloglossus
Palatoglossus
What are the intrinsic muscles of the tongue?
Superior longitudinal
Inferior longitudinal
Transverse
Vertical
Superior longitudinal OIAN
O – submucous fibrous layer, median fibrous tissue
I – margins tongue & mucous membrane
Innervation – CN XII
Action – curls tip and side superiorly, shortens tongue
Inferior longitudinal OIAN
O – root tongue, hyoid bone
I– apex of the tongue
Innervation – CN XII
Action – curls tip inferiorly, shortens tongue
Transverse OIAN
O – root tongue, hyoid bone
I – apex of the tongue
Innervation – CN XII
Action – curls tip inferiorly, shortens tongue
Vertical OIAN
O - superior surface
I - inferior surface
Innervation - CN XII
Action - flattens and broadens tongue, assists in protruding
If someone stuck out their tongue and it deviates to the right, what can we assume and what muscle is affected?
We can assume that there is a dysfunction with CN XII on the right hand side which is affecting the action of the genioglossus muscle on the right, the muscle is not working so the genioglossus muscle on the left hand side is pushing the tongue to the right and there is no corresponding genioglossus acting on the right hand side to counteract it and make the tongue go straight forward
