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Understanding Breast Changes: A Health Guide for Women

  • Updated: 03/25/2014

Breast and Lymphatic System Basics

To better understand breast changes, it helps to know what the breasts and lymphatic system are made of.

What are breasts made of?

Breasts are made of connective tissue, glandular tissue, and fatty tissue. Connective tissue and glandular tissue look dense, or white on a mammogram. Fatty tissue is non-dense, or black on a mammogram. Dense breasts can make mammograms harder to interpret.

Breasts have lobes, lobules, ducts, an areola, and a nipple.

  • Lobes are sections of the glandular tissue. Lobes have smaller sections called lobules that end in tiny bulbs that can make milk.
  • Ducts are thin tubes that connect the lobes and lobules. Milk flows from the lobules through the ducts to the nipple.
  • The nipple is the small raised area at the tip of the breast. Milk flows through the nipple. The areola is the area of darker-colored skin around the nipple. Each breast also has lymph vessels.
Anatomy of the breast

What is the lymphatic system made of?

The lymphatic system, which is a part of your body's defense system, contains lymph vessels and lymph nodes.

  • Lymph vessels are thin tubes that carry a fluid called lymph and white blood cells.
  • Lymph vessels lead to small, bean-shaped organs called lymph nodes. Lymph nodes are found near your breast, under your arm, above your collarbone, in your chest, and in other parts of your body.
  • Lymph nodes filter substances in lymph to help fight infection and disease. They also store disease-fighting white blood cells called lymphocytes.