Filiform have none; fungiform, circumvallate and foliate do
Expansion
Four papillae
- Filiform - most numerous, conical, keratinised, covering the anterior two thirds. No taste buds; purely mechanical, for gripping food
- Fungiform - mushroom shaped, scattered on the tip and sides, red because they are vascular. Few taste buds each, but numerous
- Circumvallate (vallate) - 8 to 12 large papillae in a V along the sulcus terminalis. Surrounded by a moat into which von Ebner’s glands secrete serous fluid. Many taste buds
- Foliate - vertical folds on the lateral margin, better developed in children
“Filiform have no taste; the other three do.”
The taste bud is a barrel shaped cluster of about 50 to 100 cells opening through a taste pore, containing gustatory (receptor) cells, supporting cells and basal stem cells. Receptor cells turn over every 10 days.
Five modalities: sweet, salt, sour, bitter and umami. The taste map is a myth: all modalities are detected across the whole tongue, with only slight regional variation.
Innervation splits at the sulcus terminalis: taste from the anterior two thirds by the chorda tympani (VII), from the posterior third by IX, and from the epiglottis by X. General sensation anteriorly is V3, which is why the front of the tongue has two different nerves for taste and touch.