Texas A&M University (TAMU) NUTR 301 Nutrition Through Life Exam 1 Practice Test

Milk ejection happens thanks to myoepithelial cells. These smooth-muscle–like cells wrap around the secretory units of the mammary gland (the alveoli) and, when stimulated by oxytocin, contract to squeeze milk from the alveoli into the ducts. The secretory cells themselves make the milk, the alveoli are the milk-producing sacs, and the ducts carry milk onward. The described action—surrounding secretory cells and contracting to push milk into ducts—is the role of myoepithelial cells.