Figure 6.

Brainbow‐labeling of intragemmal and perigemmal fibers associated with fungiform and circumvallate taste buds. (A) A single intragemmal fiber, seen in its entirety in the plane of this oblique section, exhibits shape irregularities immediately below and within the base of the bud (the basal lamina is indicated by dashed lines) where it branches to reach a broad region within the central bud. The endings are expanded (small arrows). (B) Drawing of the fiber in A. (C) Perigemmal fibers (arrows) ascend in the epithelium adjacent to the sides of the taste bud (TB), ending as rounded swellings in the non‐taste surface epithelium (asterisks). Intragemmal fibers (arrowheads) enter and terminate, often with swellings (small arrow) or ball‐on‐stalk endings (double small arrows) within the taste bud. Inset: small yellow/white fluorescent blobs (see text) are present in the central bud. (D) Vallate taste buds contain intragemmal fibers that reach all regions of each bud. The fibers are predominantly oriented vertically, toward the surface of the epithelium. They are branched and bear preterminal and terminal swellings. Preterminal gustatory fibers course parallel to the epithelial basal lamina and turn at right angles to enter the buds. Brainbow‐fluorescent gemmal cells (arrows) within vallate buds; the apical process of one terminates at the taste pore (P). Inset: There are few perigemmal fibers (asterisk). Scale bars: (A–C) 10 μm, (inset to A–C) 3 μm, (D) 20 μm, (inset to D) 40 μm.