The histological structure of the mammary glands varies according to sex, age, and physiological status.

What is the changes in that mamma?

- lactiferous ducts are lined by a stratified squamous (keratinized) epithelium.
- Lactiferous sinus are lined by stratified cuboidal epithelium.
- the smaller ducts leading to the lactiferous duct are lined by a simple columnar epithelium.
- Stellate myoepithelial cells located between the epithelium.
- basal lamina also wrap around the developing alveoli and become functional during pregnancy.

1.1. Breast development in puberty and in the adult:
- Before puberty, the mammary glands: lactiferous sinuses, several branches of these sinuses, the lactiferous ducts.
- During puberty, the breasts increase in size and develop a prominent nipple in female: increase ovarian estrogen increase growth and branching of lactiferous ducts accumulation of adipose tissue and connective tissues.
1.2. Breast during prenancy and lactation:
- During pregnancy, the terminal portions of the ducts branch and grow and develop secretory units known as alveoli.
- Alveoli: Alveoli are spherical collections of epithelial cells that become the active milk-secreting structures in lactation.
- During lactation, milk is produced by the epithelial cells of the alveoli and accumulates in their lumens and inside the lactiferous ducts.
- proteins include several caseins, -lactalbumin, and plasmocyte-produced IgA. Proteins constitute approximately 1.5% of human milk. Lactose, the sugar of milk, is synthesized from glucose and galactose and constitutes about 7% of human milk.
- Colostrum: the first 2 or 3 days after birth, a protein-rich thick fluid called colostrum is secreted. This high-protein secretion, rich in vitamin A , sodium, and chloride, also contains lymphocytes and monocytes, minerals, lactalbumin. It contains less fat and more protein than regular milk and is rich in antibodies (predominantly secretory IgA) that provide some degree of passive immunity to the newborn, especially within the gut lumen.
- Milk: usually produced by the 4th day after parturition, is a fluid that contains minerals, electrolytes, carbohydrates (including lactose), immunoglobulins (mostly immunoglobulin A), proteins (including caseins), and lipids. Production of milk results from the stimuli of sight, touch, handling of the newborn, and anticipation of nursing, events that create a surge in prolactin release. Once initiated, milk production is continuous, with the milk being stored within the duct system.
- Milk-ejection reflex: oxytocin is released from the posterior lobe of the pituitary. Oxytocin initiates the milk ejection reflex by inducing contractions of the myoepithelial cells around the alveoli and the ducts, thus expelling the milk.
- After menopause, involution of the mammary glands is characterized by a reduction in size and the atrophy of their secretory portions and, to a certain extent, the ducts. Atrophic changes also take place in the connective tissue.

1.3. Breast cancer, second only to lung cancer as one of the major causes of cancer-related death in women, may be of two different types: ductal carcinoma of the ductal cells and lobular carcinoma of the terminal ductules. Detection must be early, or the prognosis is poor because the carcinoma may metastasize to the axillary lymph nodes and from there to the lungs, bone, and brain.