Mammary Glands: Structure, Function, Development, Function & Diagram

The mammary glands are accessory reproductive organs unique to the members of the Class Mammalia. Its main functions include the synthesis and secretion of milk for the baby. The breast milk is aimed at providing protection, nourishment, and development for the infant. The breast milk is secreted during the lactation period of pregnancy.

This Story also Contains

1. What are Mammary Glands?
2. Structure of Mammary Glands
3. Development and Physiology of Mammary Glands
4. Function of Mammary Glands
5. Disorders and Diseases of Mammary Glands
6. MCQs on Mammary Glands
7. Recommended Video On 'Mammary Glands'

The maturation of the mammary glands is required for the production of milk under the influence of various hormones. These changes enable the breasts to function as a milk-producing organ upon parturition. Mammary glands are an important topic in the biology subject.

What are Mammary Glands?

Mammary glands are organs unique to mammals that produce and secrete milk for the nourishment of the offspring. These organs form an important part of the female reproductive system and, during the different stages of life, go through remarkable changes, mainly during puberty, pregnancy, and lactation.

Mammary glands are important for the survival of mammalian young, offering basic nutrients and antibodies through milk. This ability to nourish the young by lactation has been one of the most important adaptations that have improved survival and development for mammalian species.

Exocrine glands, like mammary glands in humans, are important for the nutrition and development of the immunity and immune system of infants. Breastfeeding promotes bonding between mother and child and is linked to several health benefits for the child and the mother.

Structure of Mammary Glands

The structure of mammary glands is somewhat complex to efficiently produce milk and secrete it. There are various intricate structural details which is necessary for it to function.

Anatomy of Mammary Glands

• Alveoli: These are small sac-like structures lined with secretory cells, where milk is produced.

• Lactiferous ducts: canals that carry milk from the alveoli to the nipple.

• Nipple and Areola: The nipple is the external opening, by which milk is excreted surrounded by the pigmented areola.

Development and Physiology of Mammary Glands

Mammary gland development and physiology reflect a tight coupling between hormones and life stages. The development of the embryo and how it is regulated by hormones is described below-

Embryonic Development

• The mammary glands arise from mammary ridges in the embryo.

• Development occurs via genetic and hormonal influences.

Hormonal Regulation

• Estrogen: Stimulates ductal growth and differentiation.

• Progesterone: Induces the development of the glandular tissue.

• Prolactin: Hormone responsible for lactation.

• Oxytocin: Initiates the milk ejection reflex in response to suckling.

Stages of Development

• Puberty: The mammary tissue grows and matures due to changes in the hormonal environment.

• Pregnancy: There is appreciable growth and differentiation of mammary glands in preparation for lactation.

• Lactation: Active production and secretion of milk to feed the infant.

• Menopause: Gradual atrophy of mammary tissue occurs due to a decrease in the level of hormones.

Function of Mammary Glands

The major function of mammary glands is the production and ejection of milk to feed the newborn. This is very essential as its the first feed to the baby and supplies with necessary nutrition and protection.

• The main purpose of mammary glands is to produce and secrete milk for the nourishment of the offspring.

• Milk Production occurs in the alveoli and then is secreted into the lactiferous ducts, where it exits at the nipple.

• Milk ejection is caused by the hormone oxytocin.

• Milk contains proteins, fats, carbohydrates, vitamins, minerals and antibodies.

• Nutritional and immunological components are important for infant development and immune protection.

Disorders and Diseases of Mammary Glands

The mammary glands are subject to various disorders and diseases, which may affect their function or overall health. Diagnosing these diseases and managing it is necessary to prevent further problems.

Common Disorders

• Mastitis: This is usually an infection that results in inflammation in the mammary gland.

• Fibrocystic Breast Changes: These are non-cancerous changes in the breast, which could form multiple lumps and cause pain.

Breast Cancer

• Risk Factors: Genetic tendency, age, hormonal factors, and lifestyle factors

• Symptoms: Lumps, changes in the shape of the breasts or their contour, skin dimpling, nipple discharge

• Prevention and Treatment: Screening regularly, healthy lifestyle, surgery, radiation, chemotherapy.

MCQs on Mammary Glands

Q1. Glandular tissues of each breast is divided into

Option 1: 15-20 mammary tubes

Option 2: 15-20 mammary ducts

Option 3: 15-20 mammary lobes

Option 4: None of these

Correct answer: 3) 15-20 mammary lobes .

Explanation:

The glandular tissue of each breast is divided into 15‐20 mammary lobes containing clusters of cells called alveoli. The cells of alveoli secrete milk, which is stored in the cavities (lumens) of alveoli. The alveoli open into mammary tubules. The tubules of each lobe join to form a mammary duct. Several mammary ducts join to form a wider mammary ampulla which is connected to a lactiferous duct through which milk is sucked out.

Hence, the correct answer is option 3) 15-20 mammary lobes.

Q2. What is correct about the mammary gland?

1. Mammary glands are exocrine glands.

2. They are modified sweat glands.

3. One pair of mammary glands is present.

4. They are present on the ventral thoracic wall.

Option 1: All of them

Option 2: Only 2

Option 3: 1 and 3

Option 4: None of them

Correct answer: (1) All of them

Explanation:

In human beings, the mammary glands are a pair of modified sweat glands situated on the ventral thoracic wall. They play a crucial role in lactation, providing nourishment to newborns. In females, the mammary glands are well-developed due to the influence of the hormones estrogen and progesterone, which regulate their growth, development, and functional activity, particularly during puberty, pregnancy, and lactation. Structurally, each mammary gland consists of glandular tissue organized into lobes and lobules, connected to the nipple through a series of ducts.

Hence, the correct option is (1) All of them

Q3. Choose the correct sequence of milk flow.

Option 1: Alveoli- mammary tubules - mammary ducts - mammary ampulla - lactiferous duct.

Option 2: Alveoli-mammary ducts - mammary tubules - mammary ampulla- lactiferous duct.

Option 3: Alveoli-mammary ampulla - mammary tubules - mammary ducts - lactiferous duct.

Option 4: Alveoli-mammary ampulla - lactiferous duct- mammary ducts - mammary tubules.

Correct answer: 1) Alveoli- mammary tubules - mammary ducts - mammary ampulla - lactiferous duct.

Explanation:

A functional mammary gland is characteristic of all female mammals. The mammary glands are paired structures (breasts) that contain glandular tissue and a variable amount of fat.

The glandular tissue of each breast is divided into 15-20 mammary lobes containing clusters of cells called alveoli. The cells of alveoli secrete milk, which is stored in the cavities (lumens) of alveoli. The alveoli open into mammary tubules.

The tubules of each lobe join to form a mammary duct. Several mammary ducts join to form a wider mammary ampulla which is connected to a lactiferous duct through which milk is sucked out.

Hence, the correct answer is option 1) Alveoli- mammary tubules - mammary ducts - mammary ampulla - lactiferous duct.

Recommended Video On 'Mammary Glands'