Tits

The breasts are modified sudoriferous (sweat) glands, producing milk in females, and in some rare cases, males. Each breast has one nipple surrounded by the areola. The areola is colored from pink to dark brown and has several sebaceous glands. In females, the larger mammary glands within the breast produce the milk. They are distributed throughout the breast, with two-thirds of the tissue found within 30 mm of the base of the nipple.

These are drained to the nipple by between 4 and 18 lactiferous ducts, where each duct has its own opening. The network formed by these ducts is complex, like the tangled roots of a tree. It is not always arranged radially, and branches close to the nipple. The ducts near the nipple do not act as milk reservoirs; Ramsay et al. have shown that conventionally described lactiferous sinuses do not, in fact, exist.

Source: Wikipedia