CBSE Class 9 Answered

Columnar and cuboidal epithelial cells often become specialised as gland cells which are capable of synthesising and secreting certain substances such as enzymes, hormones, milk, mucus, sweat, wax and saliva. Unicellular glands consist of single, isolated glandular cells such as the goblet cells. Sometimes a portion of the epithelial tissue becomes invaginated and a multicellular gland is formed. Multicellular glands are composed of clusters of cells. Most glands are multicellular including the the salivary glands.

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