All the milk from one teat is produced by the glandular apparatus of that quarter. The parenchyma of the mammary gland refers to the epithelial or glandular tissues as opposed to the stroma or connective tissue support. The milk secreting unit of the mammary gland is the alveolus Alveoli empty their contents into ducts which lead to a gland Cistern or storage area at the base of the gland. Each alveolus is a component of a lobule.
Several lobules form a lobe.
Expulsion of milk occurs through the teat canal which is kept Tightly closed by a muscle sphincter. Ducts are referred to as lobular or lobar depending on whether they serve lobules or lobes. Intralobular and interlobular refer to ducts within and between lobules. Ducts are composed of a double layer of cells while the alveolus is composed of a single layer of cells. The gland cistern drains into the teat cistern which drains via the streak canal to the exterior of the gland Teat Part of the mammary gland from which milk is extracted and suckled by the young is called the teat.