Periodontium L4 Flashcards
Name the 4 extrinsic muscles of the tongue
- genioglossus
- hyoglossus
- styloglossus
- palatoglossus
Name the 4 intrinsic muscles of the tongue
- superior longitudinal
- inferior longitudinal
- transverse
- vertical
Function of the extrinsic muscles of the tongue
Move tongue bodily (protrude/retract/depress/elevate the tongue)
Functions of intrinsic muscles of the tongue (x3)
- lengthens/shortens the tongue
- curling and uncurling of its apex and edges
- flattening/rounding of its surface
Name the 4 types of lingual papillae
- filiform papillae
- fungiform papillae
- foliate papillae
- circumvallate papillae
Location of filiform papillae
Anterior part of the tongue
Structure of filiform papillae
Cone-shaped
Connective tissue core
Keratinised epithelial cover (tough abrasive surface) ; non-keratinised epithelium in between - offers flexibility
Which lingual papillae does not contain taste buds?
Filiform papillae
Location of fungiform papillae
Anterior part of the tongue
Innervation of fungiform papillae
CN VII
Approx number of fungiform papillae taste buds per tongue
1120
Location of foliate papillae
Lateral margin of posterior aspect of tongue
Innervation of foliate papillae
Anterior: CN VII
Posterior: CN IX
Approx number of foliate taste buds per tongue
1280
Position of circumvallate lingual papillae
Anterior to the sulcus terminalis in the tongue
Innervation of the circumvallate papillae
CN IX
Approx number of circumvallate papillae
2000 circumvallate taste buds per tongue
What cell types are present in taste buds?
- type I: dark cells
- type II: light cells
- type III: receptors
- type IV: precursors of types I-III
Function of type I cells in taste buds
Type I - dark cells
- support cells
- produces taste pore substance
Function of type III cells in taste buds
Type III cells are receptors synaptically coupled to gustatory nerves
Nerve supply of taste buds on:
- posterior 1/3rd of tongue
- anterior 2/3rd of tongue
- epiglottis
posterior 1/3rd: CN IX
Anterior 2/3rd: CN VII
Epiglottis : CN X
Where are non-lingual taste buds located?
Soft palate
Epiglottis
What types of nerves are found on taste buds?
A-delta afferents, non-myelinated
Receptor mechanisms (x5)
- depolarising receptor cell potential
- open voltage gated calcium channels
- increased intracellular free calcium ions
- release of neurotransmitter
- depolarisation of different nerve endings
Functions of the tongue
- ingestion: mastication, swallowing, suckling, cleansing of mouth
- sensory: taste/gustation, touch/mechanoreception
- speech
