The milk-secreting cell clusters within the breast, which connect via lactiferous ducts to the nipple, are called:

1. Breast milk is produced by the mammary glands, which are modified sweat glands. 2. Within a glandular lobe, milk is produced by specific clusters of cells. 3. These milk-secreting clusters alveoli. 4. Milk moves from the alveoli through lactiferous ducts to the lactiferous sinuses and out through the nipple so 'areolae' (the pigmented skin area) is a different structure and is ruled out. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 27 "The Reproductive System", p.1306 §The Breasts_