Breast Feeding and Lactation-Anatomy and Physiology

Produced by:Neha Panchal

Aisha Mirenisha

Main Contents

• Terms and Definitions• Anatomical structure of female’s breast• Physiological functions of female’s breast• Milk production of breast• Definition of colostrum• Composition and role of the colostrum• Period of the breast feeding

Terms and Definitions

Anatomical Structure of Female’s Breastbreast sits atop the pectoralis muscle , atop the rib cage. The breast tissue extends horizontally (side to side)

from the edge of the sternum out of the midaxillary line. It is important to remember that a tail of breast tissue called the “axillary tail of Spence” does extend into the axilla.

Vertically: 2nd to 6th ribs; extension: below 7th to 8th ribs (posteriorly: edge of latissimus dorsi).

Connective tissue and ligaments provide support to the breast and give it its shape. Nerves provide sensation to the breast. The breast also contains blood vessels, lymph vessels, and lymph nodes.

The breast tissue is encircled by a thin layer of connective tissue called fascia. The deep layer of this fascia sits immediately on top of the pectoralis muscle, and the superficial layer sits just under the skin. The skin covering the breast is similar to skin elsewhere on the torso and has similar sweat glands, hair follicles, and other characteristic feature.

The male breast is nearly identical to that of the female breast, except that the male breast tissue lacks the specialized lobules, as there is no physiologic need for milk production by the male breast.

Anatomical Structure of Female’s BreastThe breast is mass of glandular, fatty and connective tissue. The breast is made up of:

• Lobe-breast made of 15-20 pyramid-shaped lobes; every lobe contains 20-40 lobules• Lobes-Lobules-Lactiferous duct-Lactiferous sinus- Nipple

• Lobule-glands that produce milk

• Ducts-Tubes that carry milk from the lobules to the nipple

• Fatty and Connective tissue- surrounds and protects the ducts

and lobules and gives shape to the breast

• Areola-the pink of brown, circular area around the nipple that contains small sweat glands(Montgomery), which secret moisture as a lubricant during breast feeding

• Nipple-pigmented, cylindrical structure; the area at the center of the areola where the milk comes out• Nipple and areola contains smooth muscle

Physiological Function of Female’s Breast• The breast is an organ specialized for production of milk for lactation; to provide milk to feed

infant. Milk is produced and stored by the mammary glands and released through mammary ducts and nipple;

• Sensitive nerve endings in the nipple send signals to the brain to produce the hormone oxytocin and initiate the release of milk. • Such as manual stimulation , hearing a baby crying, seeing a baby, can also cause oxytocin to be produce. • Oxytocin-causes the smooth muscle tissue surrounding the mammary gland to contract, forcing the milk out of the

mammary gland.• Breastfeeding can be a stimulation of the breast, in which sensitive nerve endings send signals to the brain. This

results in more blood flow to the nipples in response to the stimuli.

• The internal mammary artery supplies blood to the breast, which travels under the breast tissue.• The blood supply provides nutrients (oxygen) to the breast tissue.

• The breast has many blood and lymph vessels. • The lymph vessels and nodes are part of the lymphatic system, which help to fight infections.

• Lymph vessels are thin tubes that collect and move lymph fluid away from the breast to lymph nodes(bean shaped masses).

Female Breast Development

Hormones of Breastfeeding

• Milk is produced in lobules throughout the breast when they are stimulated by hormones in a woman’s body after giving birth. • Many additional changes are seen in the breast tissue during pregnancy and lactation due to the changes of the

hormones.

• Estrogen is the main female hormone. It influences female’s sexual characteristics, such as breast development, and it is necessary for reproduction. Most of the estrogen in a woman’s body is made by the ovaries, though a small amount is made by the adrenal glands .

• Progesterone is the other female sex hormone made in the ovaries. Its role is to prepare the uterus (womb) for pregnancy and the breasts for producing milk for breast-feeding (lactation).

• The breast tissue are exposed to monthly cycles of estrogen and progesterone throughout a woman’s childbearing years.• In the first part of the menstrual cycle, estrogen stimulates the growth of the milk ducts;• Progesterone takes over in the second part of a woman’s menstrual cycle, stimulating the

lobules.