Mammary Gland in Virgin Mice

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The female mouse has five pairs of nipples and mammary glands (see Diagram of Mammary Gland – In Situ). Mammary glands are embedded in adipose tissue (mammary fat pad) and consist of acini and ducts, which give mammary glands tree-like structures (best observed in a whole-mount preparation). In virgin mice, the mammary gland consists of lactiferous ducts and a few acini, the lobules type 1. The acini and ducts of mammary glands are lined by cuboidal epithelium, consisting of an inner layer of luminal secretory cells surrounded by basal myoepithelial cells. Male mice have four pairs of mammary glands but no nipples.

All micrographs depict a mammary gland derived from a virgin female mouse. The 4X micrograph illustrates a mammary gland embedded in adipose tissue. The 10X, 20X, and 40X micrographs present the acini and ducts of the mammary gland in increasing detail. In the 20X micrograph the cuboidal epithelial lining of the ducts is visible. The 40X micrograph shows the different cells present in this epithelium.