The two main structures that exist in the breast are the lobules and the ducts. The lobules are the glands that produce milk. The ducts are the tubes that carry the milk to the nipple.
Other structures that are found within the breast are:
1.Blood vessels which deliver oxygen and nutrients to the breast tissue
2. Lymph nodes which drain and filter fluid from the cells in the breast
3. Fat which helps to cushion the breast tissue
4. Connective tissue which connects all of the structures together