In bloom

In response to hormones released during pregnancy and lactation, breast tissue undergoes dramatic changes in form and function. Tree-like ducts and lobules ‘bloom’ to form clusters of spherical hollows called alveoli.

Each alveolus contains many milk-producing cells encircled by tiny muscle-like cells, revealed by yellow and purple dyes in Caleb’s high-resolution 3D image. The muscle-like cells contract in response to suckling to deliver milk into the ducts and to the infant.

With a more detailed understanding of the changes that healthy breast tissue undergoes, particularly the role of immune cells in the breast, researchers are gaining new insights into the origins and growth of breast cancers.