a-short-review-of-histology

Lactating Breast:

Under the influence of prolactin, secreted by the anterior pituitary gland, the secretory cells become activated to produce the milk
There is hypertrophy of the individual secretory cells. In turn, there is an overall increase in the size of the breast
The contraction of myoepithelial cells, under the influence of oxytocin secreted by the posterior pituitary gland, but triggered by the suckling stimulus, squeezes the secretory components of the glands to push the milk through the duct system

Micrograph of Lactating Breast Tissue:

During lactation the glandular tissue hypertrophies as milk is produced
On the right of this micrograph the active glandular tissue of the lactating breast can be seen; on the left, a large duct contains some secretion (milk)