This video provides a detailed histological tour of a section of the tongue, specifically focusing on the structures found in the lateral region, including the foliate papillae. The presenter identifies and describes the intrinsic muscle fibers (skeletal muscle with peripheral nuclei and striations), numerous serous glands (Von Ebner’s glands), and associated connective and lymphoid tissues. A comparison of the four types of lingual papillae is provided, highlighting the foliate papillae and clarifying that only filiform papillae lack taste buds. The internal structure of the taste buds, composed of both supporting and neural sensory cells, and the presence of primary lymphoid follicles are also covered.
Histological Examination of the Lateral Tongue and Foliate Papillae
0:06 Sample Identification: The section is confirmed to be tongue tissue based on the presence of serous (Von Ebner's) glands and intertwining bundles of skeletal muscle fibers (intrinsic muscles).
0:30 Skeletal Muscle Markers: Muscle fibers are identified by clear striations (in longitudinal cuts) and the distinct location of nuclei at the periphery of the fiber (in transverse cuts).
1:09 Foliate Papillae: These papillae, found on the lateral side of the tongue, are described as squared-off structures (contrasted with the "big toad stool" appearance of circumvallate papillae).
1:48 Papillae and Taste Buds: Foliate papillae contain taste buds, similar to circumvallate and fungiform papillae.
2:18 Filiform Papillae: The fourth type of papilla, the filiform, does not contain taste buds; they are spiky, hyper-keratinized areas involved in combing/handling food, resembling a cat's tongue.
2:52 Von Ebner's Glands: Serous-secreting acinar structures (Von Ebner's glands) are shown, with their ducts leading close to the taste bud surfaces.
3:34 Taste Bud Cellular Structure: Taste buds are composed mainly of supporting cells, interspersed with neural sensory cells (which appear darker and spindlier) responsible for initiating the taste impulse.
4:00 Lamina Propria: The connective tissue layer contains fibroblasts, lymphocytes, plasma cells, macrophages, and diffuse lymphoid tissue (potential MALT).
5:10 Lymphoid Tissue Identification: A collection of lymphocytes is identified as a primary follicle/nodule because it lacks a clear-cut germinal center.
5:40 Nerve Structure: A small nerve is identified by its classical appearance: wavy, foamy Schwann cells surrounding the lighter, internal axons.