Mucous glands refer to exocrine glands that secrete mucus and consist of several mucous cells, whereas the purely mucous glands are the glands of the tongue and palate, palatine glands, and posterior glands of the tongue. 1. Lingual palatine glands: located in the pharyngeal part of the lingual palatine folds, they can also extend from the posterior part of the sublingual gland to the soft palate. 2. Palatine glands: located in the glandular region of the soft palate, there are hundreds of glands in the soft palate and pituitary gland, and the shape of the ducts is irregular, with large openings in the mucous surface, the glands in this area are pure mucous glands, and the more backward the distribution of the glands, the larger the size of the glands. 3. Posterior lingual glands: located in the lateral and posterior portion of the contour papillae the ducts open in the groove between the lingual tonsillar crypt and the tonsillar follicle, this part is pure mucous glands.