This video provides a detailed histological examination of a cross-section of the tongue, identifying characteristic structures essential for its function. The analysis highlights the surface layer of non-keratinized stratified squamous mucosa and the core composed of abundant skeletal muscle fibers running in orthogonal directions, a defining feature of the tongue. The speaker identifies significant neurovascular bundles, including thick arteries and large nerves. A substantial portion of the discussion focuses on differentiating the two primary types of lingual papillae present: the sharply pointed, hyperkeratinized Filiform papillae (used for scraping and lacking taste buds) and the blunter, mushroom-like Fungiform papillae (which contain taste buds). The examination concludes by identifying the smooth underside of the organ.
Histological Examination of the Tongue
0:03 - 0:24 General Structure: The specimen is identified as non-keratinized stratified squamous mucosa. The bulk of the structure is composed of skeletal muscle fibers running in every direction, alongside blood vessels and connective tissue, instantly identifying the organ as the tongue.
0:26 - 0:49 Neurovascular Elements: Numerous nerves, small arteries (arterioles), and very thick arteries (cut transversally and obliquely) are pointed out within the muscle bundles.
0:56 - 1:06 Skeletal Muscle Identification: Muscle fibers are confirmed to be skeletal because their nuclei are located at the periphery of the fiber, and visible striations are present.
1:41 - 2:02 Filiform Papillae: The hyperkeratinized, pointy papillae are identified as Filiform papillae. Key takeaways: they function to scrape food and do not contain taste buds.
2:04 - 2:27 Fungiform Papillae: The mushroom-looking or more blunted papillae are identified as Fungiform papillae. Key takeaways: these are the papillae that contain the small taste buds on their surface.
2:46 - 3:00 Underlying Connective Tissue: The speaker points out skeletal muscle bundles cut axially and longitudinally, as well as the loose connective tissue of the lamina propria and blood vessels.
3:00 - 3:39 Vascular Review: A variety of vessels are reviewed, including thick arteries, thin-walled veins (with large lumens), and smaller arteries.
3:40 Underside of the Tongue: The area of the mucosa that is very smooth and lacks numerous papillae is identified as the probable underside or bottom of the tongue.