The mammary glands undergo differentiation during pregnancy and start producing milk through lactation towards the end of pregnancy. This helps the mother in feeding the new-born

Define mammary duct ectasia.

It is a benign (non-cancerous) breast condition in which a milk duct widens & thickens under the nipple. It causes the duct to become blocked & fluid build up inside it.

What are the functions of mammary glands?

The functions of the mammary glands are the secretion, production & ejection of milk & these functions, called lactation, are associated with pregnancy.

Define the pathway of milk flow in a mammary gland.

Alveoli or acini → Mammary tubule → Mammary duct → Mammary ampulla → Lactiferous duct → Out (through nipple)

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Mammary Glands

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Mammary Glands

The mammary glands are modified sweat glands, paired structures (breasts) that contain glandular tissue & variable amounts of fat. Highly evolved & specialized organs develop on each side of the anterior chest wall. It is an exocrine gland in all female mammals & its primary function is to secrete milk through lactation. Mammary glands are present in both sexes but well developed in females but rudimentary in males.

1.0Mammary Gland Diagram

(A) Skin: It comprises the nipple & Areola.

Nipple: The external pigmented projection in each breast, through which milk is expelled. It has a series of closely spaced openings of ducts called lactiferous ducts (15-20 ducts).

Areola: Circular pigmented area of skin surrounding the nipple contains sebaceous glands, which help to protect & lubricate the nipple during breastfeeding.

(B) Lobules: These are glandular units that produce milk.

Each lobule contains grapelike clusters of milk-secreting glands termed alveoli (alveoli ® small cavities).
The alveoli open into mammary tubules.
The alveoli are lined by epithelial cells & surrounded by myoepithelial cells, which contract to propel the milk towards the nipple.

(C) Mammary Ducts: The tubular structures transport milk from the Lobules to the nipple.

The tubules of each lobe join to form a duct.
Several ducts join to form a wider mammary ampulla which is connected to a duct known as the lactiferous duct through which milk is sucked out.
Lactiferous ducts expand into lactiferous sinuses, where milk is stored before draining into a duct.

(D) Stroma: It is a connective tissue that surrounds & supports the lobules & ducts.

It contains blood vessels, fat cells, lymphatic vessels and fibrous tissue.

2.0Mammary Gland Development

Embryonic Development:

Milk lines or mammary ridge formation: During embryonic development, mammary ridges or milk lines form around the fourth to sixth week of gestation.
Primary bud formation: By the seventh week, primary mammary buds form & these buds will develop into the mammary glands.
Secondary bud formation: The Primary buds give rise to secondary buds, which will later develop into the ductal system of the mammary gland.
At Puberty:
Ducts elongate & Branched: Under the influence of oestrogen, the mammary ducts elongate & branch. Under the influence of estrogen & progesterone during menstrual cycles, further development of lobules & alveoli occurs, preparing the gland for lactation.
Adult:

Pregnancy: During pregnancy, increased levels of progesterone, estrogen, prolactin and other hormones extensively proliferate the ducts, lobules and alveoli structure, preparing the gland for milk production.
Lactation: After childbirth, prolactin & oxytocin levels rise, which promotes milk production & ejection.

3.0Histology of Mammary Gland

4.0Anatomy of the Female Breast

Lactation :

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Mammary Glands

The mammary glands are modified sweat glands, paired structures (breasts) that contain glandular tissue & variable amounts of fat. Highly evolved & specialized organs develop on each side of the anterior chest wall. It is an exocrine gland in all female mammals & its primary function is to secrete milk through lactation. Mammary glands are present in both sexes but well developed in females but rudimentary in males.

1.0Mammary Gland Diagram

(A) Skin: It comprises the nipple & Areola.

Nipple: The external pigmented projection in each breast, through which milk is expelled. It has a series of closely spaced openings of ducts called lactiferous ducts (15-20 ducts).

Areola: Circular pigmented area of skin surrounding the nipple contains sebaceous glands, which help to protect & lubricate the nipple during breastfeeding.

(B) Lobules: These are glandular units that produce milk.

Each lobule contains grapelike clusters of milk-secreting glands termed alveoli (alveoli ® small cavities).
The alveoli open into mammary tubules.
The alveoli are lined by epithelial cells & surrounded by myoepithelial cells, which contract to propel the milk towards the nipple.

(C) Mammary Ducts: The tubular structures transport milk from the Lobules to the nipple.

The tubules of each lobe join to form a duct.
Several ducts join to form a wider mammary ampulla which is connected to a duct known as the lactiferous duct through which milk is sucked out.
Lactiferous ducts expand into lactiferous sinuses, where milk is stored before draining into a duct.

(D) Stroma: It is a connective tissue that surrounds & supports the lobules & ducts.

It contains blood vessels, fat cells, lymphatic vessels and fibrous tissue.

2.0Mammary Gland Development

Embryonic Development:

Milk lines or mammary ridge formation: During embryonic development, mammary ridges or milk lines form around the fourth to sixth week of gestation.
Primary bud formation: By the seventh week, primary mammary buds form & these buds will develop into the mammary glands.
Secondary bud formation: The Primary buds give rise to secondary buds, which will later develop into the ductal system of the mammary gland.
At Puberty:
Ducts elongate & Branched: Under the influence of oestrogen, the mammary ducts elongate & branch. Under the influence of estrogen & progesterone during menstrual cycles, further development of lobules & alveoli occurs, preparing the gland for lactation.
Adult:

Pregnancy: During pregnancy, increased levels of progesterone, estrogen, prolactin and other hormones extensively proliferate the ducts, lobules and alveoli structure, preparing the gland for milk production.
Lactation: After childbirth, prolactin & oxytocin levels rise, which promotes milk production & ejection.

3.0Histology of Mammary Gland

4.0Anatomy of the Female Breast

Lactation :

Frequently Asked Questions

What is lactation?

Define mammary duct ectasia.

What are the functions of mammary glands?

Define the pathway of milk flow in a mammary gland.

Frequently Asked Questions

What is lactation?

Define mammary duct ectasia.

What are the functions of mammary glands?

Define the pathway of milk flow in a mammary gland.

Join ALLEN!

Mammary Glands

1.0Mammary Gland Diagram

2.0Mammary Gland Development

3.0Histology of Mammary Gland

4.0Anatomy of the Female Breast

Table of Contents

Join ALLEN!

Mammary Glands

1.0Mammary Gland Diagram

2.0Mammary Gland Development

3.0Histology of Mammary Gland

4.0Anatomy of the Female Breast

Table of Contents