The submandibular glands are mixed glands. They give serous and mucous secretions. The sublingual glands make mucous only. Structure of salivary glands. The glands are inside a capsule, of connective tissue. Inside, it is made of little parts called lobules. Blood vessels and nerves go into the lobules. There are three main types of cells in the major salivary glands: Serous cells are shaped like a pyramid.
The paired submandibular glands are major salivary glands located beneath the floor of the mouth. They each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimulation their contribution decreases in proportion as the parotid secretion rises to 50%.