Breast
FEMALE, or mammary gland, consists of a series of tubes radiating from a common center, the nipple of which is situated in an areola or dark colored patch. On the surface of the latter are several (from 4 to 10) sebaceous glands, which secrete an unctuous fluid to protect the skin of the nipple, which is very thin, from the saliva of the sucking infant. The milk tubes (15 or 18 in number) enlarge into sinuses, and pass each to a separate lobe or subdivision of the breast, where they divide into twigs and branches (the lactiferous ducts), which end in minute vesicles.
The lobes are held together by fibrous tissue, and are well packed in fat, which increases sometimes to an enormous extent the apparent size of the organ.