Digestive System Part I – Oral Cavity and Salivary Glands

Taste buds are seen on the lateral surface of circumvallate papillae.  A deep cleft (C) separates the papillae.  Taste buds are barrel-shaped bodies with an opening called the taste pore (1).  Microvilli from sensory neuroepithelial cells (2) extend microvilli or taste hairs through the taste pore.  Neuroepithelial cells are taste receptor cells that transmit sensory information to cranial nerves VII, IX, and X.  Sustentacular or supporting cells (3) also have microvilli, but they do not synapse with cranial nerves.  Basal cells (4) differentiate into both neuroepithelial and sustentacular cells, and replace them about every 10 days.

The section shows the sublingual gland as a mixed gland.  Lightly stained acinar cells (blue arrows) of the predominant mucous acini are surrounded by loose connective tissue (CT).  Serous cells form demilunes of von Ebner (yellow arrows) around the bases of the secretory acinar cells of the mucous acini.  Purely serous acini are seldom found in the sublingual gland; they are nearly always found in close association with mucous acini.  Numerous darkly stained acinar cell nuclei are seen in the image.  The flattened nuclei are contractile myoepithelial cells (white arrows).