Final answer:
The mammary gland is a complex structure comprising lobules of milk-producing alveoli that drain into lactiferous ducts and then into lactiferous sinuses, which meet at the nipple. Breast size, determined by fat tissue and suspensory ligaments, does not influence milk volume. Hormones regulate lactation processes and Montgomery glands provide nipple protection.
Step-by-step explanation:
The structure of a mammary gland involves several distinct components. Mammary glands are essentially modified sweat glands where the primary functional units are the lobules, which are clusters of alveoli. These lobules drain into lactiferous ducts which themselves empty into the nipple at the surface. During lactation, these alveoli, which are balloon-like structures lined with milk-secreting cuboidal cells known as lactocytes, are surrounded by contractile myoepithelial cells. The milk produced by the lactocytes is then pushed through the lactiferous ducts during suckling into the lactiferous sinuses, eventually passing through lactiferous ducts and out of the nipple pores. The breast is also composed of adipose and collagenous tissue, with suspensory ligaments providing structural support.
Within the lactating breast, these biological processes are influenced and regulated by hormones such as estrogen, growth hormone, cortisol, prolactin, and progesterone. The quantity of milk produced is not dependent on breast size, which is primarily determined by fat tissue, but rather by the functionality of the glandular tissue.
The areola, the darkened skin around the nipple, features small bumps known as Montgomery glands. These glands secrete oils to prevent chapping and cracking of the nipple during breastfeeding, and thus aid in the lactation process.