In this video lecture, educator describes overview of Glands. Glandular epithelia are tissues formed by cells specialized to produce secretion. Glandular epithelial cells may synthesize, store, and secrete proteins (e.g.; pancreas), lipids (e.g. adrenal, sebaceous glands), or complexes of carbohydrates and proteins (e.g. salivary glands). The mammary glands secrete all 3 substances.
Glands are generally classified into two major groups. Exocrine glands & Endocrine glands. Exocrine glands can be classified according to the number of cells. According to Morphology of duct System, if a gland consists of a single secretory passage or a single system of secretory passages opening into an unbranched duct, it is called a simple gland.
The secreting portions of the glands also vary in shape. When the secreting portion is in the form of a tubule, the gland is called a tubular gland. When the secreting portion is dilated in the form of a sac (called alveolus or acinus), the gland is referred to as an alveolar or acinar gland.
Considering the shape of the fundus, simple tubular glands are further classified into three sub types. Straight simple tubular glands (e.g. intestinal crypts), coiled simple tubular glands (e.g. sweat glands) and branched simple tubular glands (e.g. principal glands of stomach and endometrial glands of uterus).
The compound glands are further classified into the following three varieties. Compound tubular glands, Compound alveolar glands & Compound tubulo-alveolar glands.