Mammary Glands

The skin over the centre of the elevation has a darkly pigmented circular area called areola.

A projection overlies the central part of the areola that is known as nipple.

The glandular tissue is divided into 15–20 mammary lobes that radiate outward from the nipple and contain clusters of milk-producing glands, called alveoli.

• Mammary glands are paired structures (breasts) located on the anterior chest wall (pectoral region)
• Each breast consists of glandular tissue and a variable amount of fat (adipose tissue)
• External features include the skin, areola, and nipple
• The areola is darkly pigmented and contains sebaceous (areolar) glands that lubricate the area during breastfeeding
• The nipple is a central projection of erectile tissue where lactiferous ducts open

• Each breast contains one complex mammary gland, which is a compound tubuloalveolar exocrine gland
• The glandular tissue is divided into 15–20 mammary lobes separated by fat and connective tissue, radiating outward from the nipple
• Each lobe contains multiple lobules; each lobule contains clusters of alveoli (acini)
• The alveolar (acinar) cells lining the alveoli synthesise and secrete milk into the alveolar lumen

Internal structure of a mammary gland

• Present in both sexes at birth but remain underdeveloped (rudimentary) in both
• At puberty, under the influence of oestrogen and progesterone, the glands undergo full structural development in females
• During pregnancy, enhanced hormonal activity causes further proliferation of lobulo-alveolar tissue in preparation for lactation
• Post-lactation or at menopause, mammary glands undergo atrophy (regression in size and activity)
• In males, mammary glands remain rudimentary throughout life due to insufficient oestrogen levels

• Mammary glands are paired structures containing 15 to 20 lobes with milk-producing alveoli, ducts, a pigmented areola, and a nipple.
• The hormone prolactin stimulates the alveoli to produce milk, while oxytocin triggers its ejection following childbirth.
• The initial milk secreted, known as colostrum, is highly concentrated with essential nutrients and antibodies for the newborn.
• Following the period of lactation or the onset of menopause, the glandular tissue naturally shrinks and undergoes atrophy.
• Weaning is the gradual developmental process of replacing a mother's milk with solid foods in an infant's diet.
• Clinically, breast cancer often presents as a painless lump, is diagnosed through mammograms or biopsies, and is treated with surgery, radiation, or chemotherapy.