Which of the following are unicellular glandular cells, which secrete mucus…

A unicellular gland is a single specialized epithelial cell that independently synthesizes and releases a secretory product, in contrast to a multicellular gland, which is a compound structure made of many secretory cells organized into ducts and acini.

Within the epithelium lining the respiratory tract, digestive tract, and other mucosal surfaces, individual flask-shaped cells store mucin granules in their apical cytoplasm and release them by exocytosis as mucus. Because each such cell functions as a self-contained secretory unit rather than as part of a multicellular ductal gland, it is classified as a unicellular glandular cell, and the mucus it releases coats and lubricates the epithelial surface.

• White Blood Cells: leukocytes are immune cells that circulate in blood and tissues to detect and respond to pathogens; they are not epithelial secretory cells and do not secrete mucus.

• Goblet Cells: individual mucus-secreting cells scattered within the epithelial lining, matching the definition of a unicellular gland.

• Nerve Cells: neurons generate and conduct electrical impulses and release neurotransmitters at synapses to communicate with other cells; they do not secrete mucus.

• Gastric Gland: a multicellular tubular structure in the stomach lining composed of several different cell types, such as mucous neck cells, parietal cells, and chief cells, working together; it is a compound gland, not a single unicellular gland.

Therefore, among the given options, Goblet Cells are the unicellular glandular cells that secrete mucus for lubrication.