The milk glands
Mammary gland · glandula mammaria
The lobes and ducts inside the breast that make milk and carry it to the nipple.
What it does
Each breast holds about 15 to 20 lobes, arranged like the spokes of a wheel around the nipple. Each lobe is a cluster of tiny sacs that make milk after a baby is born. A duct from each lobe carries the milk towards the nipple. Hormones from the pituitary gland in the brain switch milk-making on and trigger its release when a baby feeds.
Surprising fact
Mammals are named after these glands: the scientist Carl Linnaeus coined the word in 1758 from the Latin mamma, meaning breast.
Why it matters
Every mammal feeds its young with milk from these glands, from whales to platypuses. In people, the milk-making tissue only becomes fully active in late pregnancy.
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Sources
Drafted with AI help; awaiting a human fact-check against these sources.
Open in the 3D atlas · Suggest a correction · Not medical advice.
3D models: Z-Anatomy & BodyParts3D (CC BY-SA 4.0 / 2.1 JP). Card text CC BY 4.0.