Extends from oral cavity into oropharynx. Muscular organ. Covered with stratified squamous epithelium (heavier keratinized).
Covered with papillae types: 1. Filiform – soft protective. Fungiform, foliate and vallate give taste in tongue.
Tip of tongue is apex and most caudal is called root that attaches to hyoid apparatus.
Palatoglossal folds = side of tongue and join palate at top = entry into oropharynx.
Frenulum – attaches at midline to floor of mouth (rostral end of base of tongue). Either side of frenulum is sublingual caruncles – forming opening to some salivary ducts.
Extrinsic muscles = 1. Geniohyoideus – from mandible (incisive area) and runs to hyoid apparatus to draw tongue rostrally.
2. Genioglossus – arises at incisive area of mandible and fans into tongue body. Pulls apex of tongue caudally, draws body rostrally and dorsum of tongue ventrally.
3. Hyoglossus – arises from basihyoid bone and runs into tongue (lateral genioglossus). Draws tongue caudally.
4. Styloglossus – arises at stylohyoid and runs lateral to hyoglossus and draws tongue caudally and dorsally (base of tongue).
5. Mylohyoideus – transverse sling that runs from side to side of mandible. Supports extrinsic muscles of tongue.
Development = from 4 swellings on floor of pharynx.
Lateral swellings – body and apex, 1st and 2nd arches. Gives general sensation by CN5 and taste sensation by cranial nerve 7.
Proximal swelling – root of tongue sensation via CN9 and CN10.
Median swelling – tongue innervated by CN12 and all motor function through this nerve.