Like other organs in the female reproductive system, the mammary gland responds to hormonal changes with marked structural structures.
(Note that normal breast tissue is mostly adipose; glandular tissue typically comprises only a small proportion of a breast.)
- Pathology. The high incidence (and mortality) of breast cancer gives special clinical significance to this organ. For a micrograph of breast cancer, see Webpath. For eloquent essays treating issues related to breast cancer, see Ira Pilgrim. See WebPath for other topics related to cancer. Difficulties in accurate diagnosis of breast cancer (especially ductal carcinoma in situ) were reported by Stephanie Saul in The New York Times, 19 July 2010.
In the inactive state, mammary gland tissue appears to consist of ducts only, separated by extensive fibrous and adipose connective tissue stroma. Adipose tissue is concentrated between lobules.
During pregnancy and lactation, the ducts extend and their secretory ends enlarge. Secretory cells acquire large, lipid-containing vesicles that resemble mucous cells (although the secretory product is milk, not mucous). Organization is not as precise (no neat alveoli) as in most other large exocrine glands.
Myoepithelial cells surround the secretory units and, under neural stimulation, forcibly expel their contents.
Bands of smooth muscle may be found in subcutaneous breast tissue, especially in the vicinity of the nipple.
SIUC / School
of Medicine / Anatomy / David
Last updated: 20 May 2022 / dgk