Head and Neck: Special Organs in the Head (Tongue)

What is the structural definition of the Tongue?

Mobile, muscular organ consisting of a mass of striated muscle covered with mucous membrane

What are the primary functional roles of the Tongue?

Mastication, gustation, deglutition, articulation, and oral cleansing

How is the tongue divided region-wise between mouth and pharynx?

Anterior 2/3 located in the mouth; Posterior 1/3 located in the pharynx

What divides the tongue into symmetrical right and left halves?

Median groove / median sulcus

What are the superior attachments of the tongue?

Styloid process and soft palate

What are the inferior attachments of the tongue?

Mandible and hyoid bone

What is the tongue Root, and where does it attach?

Inferior, relatively fixed part attached to hyoid and mandible (corresponds to posterior 1/3)

What part of the tongue corresponds to the Body?

Anterior 2/3

What is the orientation of the tongue Apex?

Pointed anterior end

What is the Sulcus Terminalis?

V-shaped sulcus dividing the upper surface of tongue into anterior (oral) and posterior (pharyngeal) parts

What is the Foramen Cecum, and what originated here?

Small pit at apex of V-shaped sulcus terminalis; site of origin of Thyroglossal duct

What are Lingual Papillae, and where are they located?

Small nipple-shaped projections on anterior 2/3 of tongue dorsum

How are Vallate (Circumvallate) Papillae arranged?

In a "V" shape directly in front of Sulcus terminalis

What is the shape and distribution of Fungiform Papillae?

Mushroom-shaped projections scattered on sides and apex of tongue

What is the shape and arrangement of Filiform Papillae?

Slender conical projections arranged in rows parallel to Sulcus terminalis

What is the characteristic of Foliate Papillae in humans?

Rudimentary

What is the main function of Intrinsic Tongue Muscles?

Alter the SHAPE of the tongue

What are the four Intrinsic Tongue Muscles?

Superior longitudinal, inferior longitudinal, transverse, and vertical

What is the main function of Extrinsic Tongue Muscles?

Alter the POSITION of the tongue

What is the action of the Palatoglossus muscle?

Elevation of tongue

What is the action of the Styloglossus muscle?

Retraction of tongue

What is the action of the Hyoglossus muscle?

Depression of tongue

What is the action and feature of the Genioglossus muscle?

Protrusion of tongue; comprises bulk of tongue

Which nerve innervates tongue muscles, and what is the exception?

All muscles (intrinsic/extrinsic) innervated by Hypoglossal nerve (CN XII) EXCEPT Palatoglossus (Vagus nerve / CN X via pharyngeal plexus)

Which nerve supplies motor innervation to the anterior 2/3 of the tongue?

CN XII (Hypoglossal nerve)

Which nerve supplies motor innervation to the posterior 1/3 of the tongue?

CN XII (Hypoglossal nerve) EXCEPT Palatoglossus supplied by pharyngeal plexus (CN X)

Which nerve provides GENERAL sensation to the anterior 2/3 of tongue?

CN V3 (Lingual nerve of Mandibular division)

Which nerve provides SPECIAL sensation (taste) to the anterior 2/3 of tongue?

CN VII (Chorda tympani of Facial nerve)

Which nerve provides BOTH general and special sensation to the posterior 1/3 of tongue?

CN IX (Glossopharyngeal nerve)

Which nerve innervates Vallate Papillae for general sensation and taste?

CN IX (Glossopharyngeal nerve)

Which nerve provides general and taste innervation to the Epiglottic region?

Internal laryngeal nerve of Vagus nerve (CN X)

What is the origin and branches of the Lingual Artery?

Originates from External carotid artery; branches into Dorsal lingual, Deep lingual, and Sublingual

Where does the Lingual Vein drain?

Internal jugular vein

Where does lymph from the posterior 1/3 of the tongue drain?

Superior deep cervical LN

Where does lymph from the medial part of anterior 2/3 of tongue drain?

Inferior deep cervical LN

Where does lymph from the lateral part of anterior 2/3 of tongue drain?

Submandibular LN

Where does lymph from the apex of the tongue drain?

Submental LN

What is the core tissue and mucosal covering of the tongue?

Core of striated muscle covered by adherent mucosa

What is the histological appearance of Filiform Papillae?

Very numerous, conical, heavily keratinized

What is the histological appearance of Fungiform Papillae?

Lightly-keratinized, mushroom-shaped

What is the histological appearance of Foliate Papillae?

Rudimentary, parallel ridges on each side of tongue

What is the histological appearance of Vallate Papillae?

Large with moat-like groove, aligned in front of sulcus terminalis

Where are Von Ebner's Salivary Glands located?

On vallate papillae

Where are Nuhn and Blandin Glands located?

Under the tongue apex (Anterior lingual glands)

What are Gustatory (Taste) Cells in taste buds?

Elongated cells with microvilli projecting toward a taste pore

What are Supportive Cells in taste buds?

Slender cells surrounding taste cells

What are Stem Cells in taste buds?

Slowly-dividing basal cells