HISTOLOGY OF TONGUE By Dr. Sobia Ibrahim Assistant Professor Anatomy, KEMU.

HISTOLOGY OF TONGUE

By Dr. Sobia Ibrahim

Assistant Professor Anatomy,

KEMU

• Tongue is a muscular organ projecting into the oral cavity from its inferior side

• Organ of speech• Organ of taste• It helps in

swallowingand plays a role in digestion

• Three subdivisions• Root/base• Body• Tip

Tongue is basically a mass of striated muscle covered by

mucous membrane

Lingual muscles are arranged in bundles that run in three

planes; longitudinal, transverse, vertical

Muscles fibers firmly adherent to mucous membrane.

Between muscle fibers are gland

Mucous- at base

Serous- in body

Mixed- near tip

It has two surfaces Dorsal (superior) Ventral (inferior)Dorsal is roughened bcz of papillaeVentral is smooth

Grossly dorsal surface is divided into anterior 2/3 and posterior 1/3 by sulcus terminalis

PAPILLAE Mucosal irregularities and elevations in different forms

and functions Present anterior to sulcus terminalis on dorsum of

tongue These papillae and associated taste buds constitute

the specialized mucosa of oral cavity Filliform Fungiform Circumvallate Foliate

PAPILLAE OF TONGUE

FILLIFORM PAPILLAE

Smallest and most

numerous in humans

Conical

Heavily keratinized

Lacks taste buds

Distributed over entire

anterior dorsal surface

Provides rough surface

FUNGIFORM PAPILLAE Less numerous

Mushroom shaped

Lightly keratinized

Covering epithelium thin

CT core with blood vessels

Taste buds on upper

surface

Rich blood supply give its

red color

VALLATE (CIRCUMVALLATE) PAPILLAE

Least numerous

Largest in size

Abundance of taste buds

Size = 1-3 mm & number is

8-12

Lie anterior to sulcus

terminalis

Surrounded by groove

Ducts of deeply located

serous glands (von Ebner’s)

open into groove

FOLIATE PAPILLAE Poorly developed in

humans

Forms furrows on

posterolateral aspect of

tongue

Contain taste buds

TASTE BUDS

Receptors for taste sensation Oval, pale staining bodies Extends through thickness of epith A small opening on epithelial

surface at the apex of taste bud is Taste pore

Sensations Sweet & salt- tip Sour- sides Bitter - back

Consists of 50-75 cells Three principal cells Neuroepithelial/ Gustatory cells having microvilli Supportive cells Stem cells Rest on basal lamina Gustatory cells supplied by sensory axon

POSTERIOR 1/3

Irregular, nodular surface

Lingual tonsil (Waldeyer’s ring)

Crypts