Tongue- Introduction, Functions, Uses ,Summary

The tongue is a muscular organ located in the oral cavity.

It plays key roles in taste, speech, chewing, and swallowing.

Covered by a mucous membrane and contains taste buds.

1. TONGUE

2. Introduction The tongue is a muscular, sensory, and multifunctional organ in the oral cavity. Primary functions : Taste detection (gustation) Speech production (articulation of sounds) Food manipulation during chewing and swallowing Touch, temperature, and pain perception Traditional view : In the five-element philosophy , the tongue is linked to the Fire element .

3. Regions of the Tongue Divided into three regions: Tip (Apex) – the frontmost part, highly sensitive to sweet and salty tastes. Body (Middle) – large central portion; involved in taste and food manipulation. Root (Base) – posterior part, anchored to the hyoid bone and connected to the throat. The tongue is covered by stratified squamous epithelium , some of which is keratinized for protection.

4. Musculature of the Tongue Intrinsic Muscles Extrinsic Muscles

5. Intrinsic Muscles Located within the tongue. Responsible for changing shape : flattening, lengthening, curling. Include: Superior longitudinal – shortens tongue, curls tip upward. Inferior longitudinal – curls tip downward. Transverse – narrows and elongates tongue. Vertical – flattens and broadens tongue.

6. Extrinsic Muscles Originate from bones and insert into the tongue . Responsible for gross movements (e.g., protrusion, retraction). Include: Genioglossus – protrudes and depresses tongue. Hyoglossus – pulls tongue down and back. Styloglossus – retracts and elevates tongue.

7. Papillae – Surface Structures of the Tongue Papillae are small, nipple-like projections on the tongue's surface that may contain taste buds . Types of Papillae: Filiform Papillae Fungiform Papillae Circumvallate Papillae oliate Papillae

8. Filiform Papillae : Thin, cone-shaped, most numerous. Do not contain taste buds . Function: sense touch, texture , and temperature.

9. Fungiform Papillae : Mushroom-shaped. Located mainly on the tip and sides of the tongue. Contain taste buds for sweet, salty, and umami . Circumvallate Papillae : Large, arranged in an inverted V-shaped row at the back of the tongue. Contain hundreds of taste buds. Foliate Papillae : Leaf-shaped, located on the posterior lateral edges . Have taste buds, especially in children.

10. Taste Buds and Taste Perception Taste buds are specialized clusters of gustatory cells located within papillae. Each bud contains 50–150 receptor cells . Receptor cells detect chemical substances dissolved in saliva and send signals to the brain. Types of taste sensations : Sweet Salty Sour Bitter Umami (savory, associated with glutamate) Taste buds are regenerated every 10–14 days .

11. Taste Zone Distribution (Classic Model) While all tastes can be detected across the tongue, certain areas are more sensitive to specific tastes: Tip – Sweet Front sides – Salty Back sides – Sour Back center – Bitter This model is simplified; modern research shows more overlap in taste regions.

12. Nerve Supply of the Tongue Anterior 2/3 (front part) : Taste : Facial nerve ( Cranial Nerve VII , via chorda tympani) Touch/temperature : Mandibular branch of the Trigeminal nerve (CN V) Posterior 1/3 (back part) : Taste & sensation : Glossopharyngeal nerve (CN IX) Base of tongue and epiglottis : Taste & sensation : Vagus nerve (CN X) Motor supply to muscles : Hypoglossal nerve (CN XII)

13. Other Functions of the Tongue Speech : Helps in articulation of consonants and vowels by altering shape and position. Swallowing : Pushes food toward the oropharynx . Initiates the deglutition reflex . Cleaning : Helps clean teeth and oral cavity. Immunity : Base of tongue contains lingual tonsils , part of the immune system.

14. Summary The tongue is a complex muscular organ involved in taste, speech, swallowing, and tactile sensation. Contains specialized surface structures (papillae) with taste buds . Has intricate nerve supply for taste, touch, and movement. Represents the Fire element in traditional systems, reflecting its active, transforming role.