Breast is the upper body of the chest. It contains the mammary glands and is made of three types of tissues: connective, glandular and fatty. It is largely made up of fatty cells. In females the estrogen hormone influences the growth of this layer and in males the testosterone suppresses this layer.
The breast in whole has lobules, ducts, nipple and areola. Lobules are the glands in breast that make milk due to hormonal stimulation, this milk in lactating females is carried to the nipple through the breast ducts. Areola is the pigmented area surrounding the nipples. Nipple is at the tip of the breast and it is the small raised area of the breast.
The breast also has lymph nodes. Human body has a defense system called the lymphatic system which consists of these lymph nodes and lymph vessels. They secrete a body fluid called lymph and white blood cells which are responsible for the immune system of the body. This fluid is secreted by the thin tubes called lymph vessels into the lymph nodes which are bean shaped. These lymph nodes are present in your breast and also in the surrounding tissue like in other parts of the body.