What is the mammary gland?
The
mammary gland is an important exocrine gland found in mammals, responsible for the production of milk. It is composed of a complex network of ducts and lobules, surrounded by adipose tissue and connective tissue.
How does the mammary gland develop during embryogenesis?
Mammary gland development begins during embryogenesis with the formation of the
mammary ridge or milk line, which appears as a thickening of the ectoderm. This ridge extends from the armpit to the groin but usually regresses except at specific locations where the mammary glands will form. The epithelial cells then proliferate and invade the underlying mesenchyme to form the primary mammary bud. This bud undergoes branching morphogenesis to form a tree-like structure of ducts.
What changes occur in the mammary gland during puberty?
During puberty, the mammary gland undergoes significant changes due to the influence of hormones such as
estrogen and
progesterone. These hormones stimulate the further development and elongation of the ductal system, as well as the formation of terminal end buds. There is also an increase in the surrounding adipose tissue, giving the breast its characteristic shape.
What happens to the mammary gland during pregnancy and lactation?
Pregnancy induces profound changes in the mammary gland, driven by hormones such as
prolactin, estrogen, and progesterone. The glandular tissue proliferates extensively, with alveoli forming at the ends of the ducts. These alveoli are lined with secretory epithelial cells that produce milk. After childbirth, the milk is secreted into the ductal system and transported to the nipple for breastfeeding.
What is the role of myoepithelial cells in the mammary gland?
Myoepithelial cells play a crucial role in the function of the mammary gland. These contractile cells are located between the secretory epithelial cells and the basement membrane. During lactation, they contract in response to oxytocin, facilitating the expulsion of milk from the alveoli into the ducts.
How does the mammary gland change during menopause?
Menopause leads to a decline in circulating estrogen levels, resulting in the involution of the mammary gland. The glandular tissue atrophies, and there is a reduction in the number of ducts and lobules. The adipose and connective tissues become more prominent, leading to changes in the overall structure and appearance of the breast.
