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Structure of the breast

The structure of the breast

  • The human breast contains fatty tissue, support tissue and milk-making glands.
  • Human milk is produced inside these lobes of glands.
  • The glands contain clusters of alveoli. These are little hollow sacks containing milk-making cells around the outside, and milk that has been produced in the middle.
  • Tubes, called ducts, carry the milk from the alveoli towards the nipple.
  • When a human baby/child breastfeeds or a breastfeeding woman expresses (and the let-down reflex is triggered), the milk flows out of the nipple via tiny openings called duct openings.

The size of the breast is not related to how well it can make milk.

  • The amount of milk stored in breasts varies between women; however, it isn’t always to overall breast size.
  • Women with a smaller storage capacity in their breasts might need to breastfeed their babies more often than women with a larger capacity.
  • It’s important to remember that a smaller breast storage capacity is only one possible reason a baby may feed often.
  • Many women store more milk in one of their breasts than the other (because that breast has a larger storage capacity).
  • Babies might spend longer feeding on the side with a bigger capacity. This is perfectly normal.
  • Finally, remember that feeding patterns (such as how often or how long they feed from each breast) can vary between babies born to the same mother.

 Breast anatomy


breastfeeding and nipple care

Breastfeeding: breast and nipple care

Breastfeeding: Breast and Nipple Care tells you what to expect as your breasts change during pregnancy and briefly covers how breastfeeding works.

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© Australian Breastfeeding Association Reviewed March 2020

Last reviewed: 
Jun 2020