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Understanding Breast Changes: A Health Guide for Women

  • Posted: 01/01/2011

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.


Glossary Terms

breast density (brest DEN-sih-tee)
Describes the relative amount of different tissues present in the breast. A dense breast has less fat than glandular and connective tissue. Mammogram films of breasts with higher density are harder to read and interpret than those of less dense breasts.
connective tissue (kuh-NEK-tiv TIH-shoo)
Supporting tissue that surrounds other tissues and organs. Specialized connective tissue includes bone, cartilage, blood, and fat.
duct (dukt)
In medicine, a tube or vessel of the body through which fluids pass.
gland (gland)
An organ that makes one or more substances, such as hormones, digestive juices, sweat, tears, saliva, or milk. Endocrine glands release the substances directly into the bloodstream. Exocrine glands release the substances into a duct or opening to the inside or outside of the body.
infection (in-FEK-shun)
Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.
lobe (lobe)
A portion of an organ, such as the liver, lung, breast, thyroid, or brain.
lobule (LOB-yule)
A small lobe or a subdivision of a lobe.
lymph (limf)
The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.
lymph node (limf node)
A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.
lymph vessel (limf ...)
A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.
lymphatic system (lim-FA-tik SIS-tem)
The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.
lymphocyte (LIM-foh-site)
A type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue. The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses. A lymphocyte is a type of white blood cell.
white blood cell (hwite blud sel)
A type of immune cell. Most white blood cells are made in the bone marrow and are found in the blood and lymph tissue. White blood cells help the body fight infections and other diseases. Granulocytes, monocytes, and lymphocytes are white blood cells. Also called leukocyte and WBC.