Note the myoepithelial cells contain contractile fibers that help in excreting milk with the help of oxytocin. The epithelial milk line lumen and are secretory that synthesize milk.
picture of mammary alveolus. The myoepithelial cells provide the contractile force to secrete milk. The epithelial milk secreting cells secrete the milk.
*Myoepithelial fibers surround the outside of the alveolus *Secretory epithelial cells line the inside of alveolus that synthesize milk which fills the alveolar lumen. *Myoepithelial contractile fibers provide the mechanism for milk ejection from the alveolar lumen into the capillary milk ducts *Milk flows from the capillary milk ducts into the intralobular ducts.
Size, shape, and weight of breast
*Vary greatly by stage of development, physiologic state, and phenotype. *Non-pregnant; 200gms *Pregnancy: 500gms *Lactating: 600gms