This video provides a histological examination of a salivary gland specimen, identifying it as the sublingual gland based on its predominantly mucinous composition, contrasting it with the parotid (100% serous) and submandibular (mixed) glands. The analysis differentiates various duct structures, specifically large interlobular ducts found within fibrous septa (lined by simple columnar epithelium) and smaller intralobular ducts (striated and intercalated ducts). Detailed morphological differences between mucous (watery cytoplasm, flattened basal nuclei) and serous (pink cytoplasm, central nuclei) acini are highlighted, along with the identification of associated connective tissue elements like plasma cells and lymphoid tissue.
Histological Examination of the Sublingual Salivary Gland
0:00 Salivary Gland Structure: The gland features a capsule and fibrous tissue septa, which divide the tissue into lobules. Ducts within the septa are identified as interlobular ducts.
0:31 Gland Identification: In contrast to the parotid (100% serous) and submandibular (50-60% serous), this gland is characterized by being almost entirely mucinous (mucous acini), confirming it as a sublingual gland.
0:57 Intralobular Ducts: The lobules contain numerous intralobular ducts, including those with abundant red cytoplasm (striated ducts) and smaller ducts with very little cytoplasm (intercalated ducts).
1:56 Mucous Acini Morphology: Mucous acini, responsible for lubrication, feature nuclei that are displaced and flattened at the base of the cell, with very watery cytoplasm.
2:18 Serous Acini Morphology: Serous acini (rare in this sublingual specimen) have non-displaced nuclei and pinkish, more stainable, less watery cytoplasm.
3:00 Interlobular Duct Epithelium: The larger interlobular ducts within the fibrous septa are noted to be lined by simple columnar epithelium (non-ciliated, non-stratified).
3:46 Identification of Plasma Cells: The speaker demonstrates the classical histological features of a plasma cell: a round, off-center nucleus with peripherally dispersed chromatin and a small white area in the cytoplasm.
4:16 Lymphoid Tissue: Lymphoid tissue is expected within salivary glands (sometimes as entire lymph nodes, especially in the parotid). The current specimen shows individually dispersed lymphoid cells.
Key Takeaway: The sublingual salivary gland is histologically identified by its overwhelming predominance of mucous/mucinous acini.