(N/A) The mammary glands are paired structures (breasts) that contain glandular tissue and variable amounts of fat.
$1$. The glandular tissue of each breast is divided into $15-20$ mammary lobes containing clusters of cells called alveoli.
$2$. The cells of alveoli secrete milk,which is stored in the cavities (lumens) of alveoli.
$3$. The alveoli open into mammary tubules. The tubules of each lobe join to form a mammary duct.
$4$. Several mammary ducts join to form a wider mammary ampulla,which is connected to the lactiferous duct through which milk is sucked out.
$5$. The pathway of milk secretion is: Alveoli $\rightarrow$ Mammary tubules $\rightarrow$ Mammary duct $\rightarrow$ Mammary ampulla $\rightarrow$ Lactiferous duct $\rightarrow$ Nipple.