Mammary

Mammary relates to the mammary glands, a pair of modified sweat glands located in the chest or thoracic region in most mammals. In humans they are situated on the anterior chest and typically referred to as breasts; in other species they may be located elsewhere on the body. The mammary gland consists of glandular tissue organized into lobes and lobules, a ductal system leading to the nipple, and surrounding adipose tissue that varies with body and age.

Mammary gland development begins in embryogenesis and is greatly influenced by hormones. At puberty, estrogen and progesterone stimulate ductal growth and lobuloalveolar development. During pregnancy, hormones induce further differentiation of secretory cells. Lactation is primarily controlled by prolactin, with oxytocin triggering milk ejection; mechanical stimulation of the nipple promotes release of these hormones. Colostrum precedes mature milk in the initial days after birth and provides immune protection.

In humans, lactation can continue for months or years and may be affected by weaning, health, and medications. Milk contains water, fats, proteins, lactose, vitamins, minerals, and immune components. Across mammals, the presence of mammary glands is a defining feature; the number of glands and nipples, as well as lactation patterns, vary greatly among species.

Clinically, the term mammary is used in contexts such as breast health and disease. Common concerns include mastitis, benign breast conditions, and breast cancer. In males, breast tissue is usually small but remains susceptible to similar pathologies in rare cases. The study of mammary glands encompasses anatomy, physiology, development, lactation biology, and oncology.