Components of the Breast
There are 2 primary components. These are milk producing and transporting tissues and structural tissues.
“Surface” of the Breast
The surface of the breast “consists” of the skin that protects the deeper structures as well as the nipple and areola.
The nipple is the protruding part of the breast, usually almost central in position and darker than the surrounding skin. Nipples can be flat, round or conical. Nipples “pores” (openings) are found in the nipple, which enable the baby to receive milk during breast-feeding. The nipple also contains sebaceous glands (oil secreting glands) that produce small amounts of lubricant. The only structure of the breast that has muscles is the nipple.
The areola is the circular area surrounding the nipple. The exact colour depends on person’s skin tone. This is usually darker than the skin. The colour also changes over time with puberty, menstruation and pregnancy.
Small pimply bumps on the areola are Montgomery’s Tubercles, which secrete an oily substance that lubricates and protects the nipple.
Inside the Breast
Within the breast are 15-20 lobes, each made up of smaller lobules. The lobules are the milk glands.
Connected to the lobules is a system of ducts (tubes), which transport milk from lobules to the nipple. The functioning portion of the breast is referred to as the glandular tissue.
Structural tissues
Fatty tissue, Connective tissue, Nerves, Blood and Lymph systems
Fatty tissue and connective tissue surround the breast's milk producing glands. Connective tissue, which is fibrous in nature, supports and contains the functional tissue, as well as the fatty tissue. The fatty tissue serves to cushion and protect the structures of the breast and to give the breast shape. Even small breasts in lean women are seldom composed of less than 1/3 fat.
The nerves provide triggering mechanism for milk production and release. Nerves also contribute to sexual pleasure. Sensitivity of the breasts varies throughout the month. They are usually more sensitive during ovulation and less sensitive during menstruation. Sensitivity is also increased during sexual activity.
Other tissues of breasts:
1. Blood vessels: They serve the same function as elsewhere in the body. Blood vessels transport nourishment and oxygen to the cells.
2. Fluids containing nutrients such as proteins, fats and sugars pass through tiny blood vessels called capillaries to the cells, which then absorb and use the nutrients.
3. The lymphatic system absorbs excess blood fluids from the tissues and eventually returns these fluids to the circulatory system.
4. Lymph nodes are specialised glands found in clusters throughout the body. They function as filters in the lymph vessels, trapping bacteria, toxins and cast off cell parts. Most of the lymph produced within the breast flows into the nodes in the armpit.
5. The chest wall muscles, the pectoral muscles are located behind the breasts’ functional and supportive tissues. Behind the muscles is the rib cage. The breasts rest on these muscles.
Size and Shape of Breast
There is no “normal” size for breasts. The size of the breast depends on heredity and the amount of fatty tissue present. Larger breasts usually contain more fatty tissue. Usually one breast (the left) is larger. Milk production does not depend on breast size. Breast size also does not influence chance of getting breast cancer.
Breasts are tear shaped, conical, round etc. Shape and size varies greatly and has no impact on function. Breasts extend up to the collarbone and out to the armpits.
The male breast
Not to be left out, in males, there is also breast tissue but normally the glandular elements remain undeveloped. It is about similar to the breast of a pre-adolescent girl. It primarily consists of a few branching ducts lined by flattened cells and surrounded by connective tissue. The tissue is capable of responding to hormonal stimulation. Enlargement of the male breast due to growth of the ducts and supporting tissues is known as gynaecomastia. Approximately 40% of adolescent boys may experience temporary enlargement of the breast, probably in response to hormones secreted by the testes. Typically this will disappear within a year or two.
In older men, several commonly used drugs and a number of diseases may stimulate breast growth. The hormone, estrogen may be used in the treatment of prostate cancer. Digitalis (a drug for heart disease) reserpine, spironolactone (for high blood pressure), ergotamine (for migraines) and phenytoin (for fits/epilepsy) are known to be associated with gynaecomastia. Breast enlargement can also occur in cancer of the testes or adrenal glands, liver cirrhosis, chronic renal dialysis and a chromosomal disorder known as Klinefelter’s syndrome. Klinefelter’s is associated with increased incidence of breast cancer.
Fat men may accumulate fat and the breasts appear enlarged but this is not true gynaecomastia.
