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1800-102-2727What comes to mind when you hear the word ‘mammals’? The first thing that we are reminded of is that mammals give birth to their young ones and feed and nurture them till they grow up. Where do you think ‘mammals’ gets their name from? They get it from the presence of mammary glands in their body which is unique to the members of class Mammalia.
We all have seen women around us breast-feeding their children since the time of birth of the child to an age of around 2-3 years. Do you ever wonder how a human mother produces milk to feed her child? This is where the mammary glands present in the breast of mammalian females, including humans, come into play. Come let us learn more about these unique glands present in human females.
Table of Contents:
All female mammals have a characteristic feature and that is the presence of a functional mammary gland. These glands help to nourish the young ones by feeding them the milk produced by the mammary glands in the lactating mothers.
Each breast is a variable-sized hemispheric projection situated anterior to the pectoralis major muscles on the front wall of the chest. The pectoralis muscle, which runs from shoulder to breast bone, is a flat muscle in the chest.
Mammary glands are under developed stage until puberty. Once the female attains puberty, they begin to develop under the influence of oestrogen and progesterone hormones.
Externally, each breast has a pigmented projection which is referred to as the nipple. Nipple possesses a set of closely spaced openings of ducts called lactiferous ducts. These are the ducts from where milk emerges. Surrounding the nipple, there is a circular area of pigmented skin which is termed as the areola. It is a rough surface and contains numerous sebaceous gland.
The breast is supported by strands of connective tissue known as the suspensory ligaments of the breast (Cooper's ligaments). The suspensory ligaments loosen with age or due to excessive strain caused due to long-term jogging or high impact aerobics.
A mammary gland is a modified sudoriferous (sweat) gland that produces milk, and is found within each breast. The mammary gland of each breast has glandular tissue composed of 15-20 mammary lobes or mammary compartments that are separated by variable amounts of adipose tissue.
Each mammary lobe consists of clusters of milk secreting cells known as alveoli which secrete milk and store it in the cavities (lumens) of the clusters or alveoli. Alveoli are embedded in the fibrous connective tissue. The fibrous connective tissue supports alveoli and ducts. The fatty adipose tissue is present between the lobes that cover the surface of mammary glands.
Each alveoli opens into mammary tubules. A mammary duct is formed when tubules emerging from each lobe join together. A mammary ampulla is formed when several mammary ducts merge. Mammary ampulla is further connected to the lactiferous duct through which milk is sucked out.
There are two types of mammary glands that are described below:
The breast performs the following functions:
The mammary glands in males are rudimentary and not well-developed like in females. They do not play any role in nursing the new-borns. Sometimes hyposecretion of androgens or hypersecretion of estrogens in males can cause the male mammary glands to swell up. This condition is known as gynaecomastia.
Breast cancer is a type of cancer that initiates in the breast. At a given time, it can develop in both breasts. When breast cells start to divide uncontrollably, then the condition is known as breast cancer. It is the most common type of cancer diagnosed in females. It can start from different parts of the breast. Breast cancer spreads in the body when the cancer cells reach the blood or lymph. These cancer cells are carried to other parts of the body through these connective tissues. The two common types of breast cancer are:
The commonly seen symptoms of breast cancer are enlisted below:
The causes of breast cancer can be hormonal, environmental or lifestyle based. In some cases, it occurs because of the complex interaction between the genetic makeup and environment. Breast cancer can also be inherited in which cancers are linked to gene mutations that are passed through generations.
Question 1. The alveoli of the mammary gland opens into which of the following structures:
a. Mammary ampulla
b. Mammary tubules
c. Mammary lobes
d. Mammary duct
Solution: The cells of alveoli secrete milk that are stored in the cavities of alveoli. Each alveoli opens into mammary tubules. The tubules are further joined to form the mammary duct. Hence, the correct option is b.
Question 2. Under the influence of which hormone(s), mammary glands develop?
a. Oestrogen
b. Progesterone
c. Oxytocin
d. Both a and b
Solution: Until puberty, the mammary glands are not fully developed. When a female reaches puberty, oestrogen and progesterone hormones begin to influence its development. Hence, the correct option is d.
Question 3. Study the given diagram and choose the option which represents the correct labelling.
a. A - mammary ampulla, B - mammary tubule, C - lactiferous duct, D - mammary duct
b. A - mammary tubule, B - mammary duct, C - mammary ampulla, D - lactiferous duct
c. A - mammary duct, B - mammary tubule, C - lactiferous duct, D - mammary ampulla
d. A - lactiferous duct, B - mammary duct, C - mammary tubule, D - mammary ampulla
Solution: Each alveoli opens into mammary tubules (A). A mammary duct (B) is formed when tubules emerging from each lobe join together. A mammary ampulla (C) is formed when several mammary ducts merge which is further connected to the lactiferous duct (D) through which milk is sucked out.
Thus, the correct option is b.
Question 1. What are the four common symptoms of breast cancer?
Solution: The four common symptoms of breast cancer are:
Question 2. In humans which type of mammary glands are present?
Solution: In humans, complex mammary glands are present. This type of gland contains many simple mammary glands that serve only one nipple.
Question 3. What are the three common functions of the breast?
Solution: The common functions of the breast are enlisted below:
Question 4. What are the common causes of breast cancer?
Solution: Breast cancer can be caused by hormonal or environmental reasons. Gene mutations linked to cancer cells can also be inherited from ancestors.
Question 5. How do breasts produce milk?
Solution: A mammary gland is a modified sweat gland that produces milk, and is found within each breast. The mammary gland of each breast has glandular tissue composed of 15-20 mammary lobes or mammary compartments that are separated by variable amounts of adipose tissue.
Each mammary lobe consists of clusters of milk secreting cells known as alveoli which secrete milk and store it in the cavities (lumens) of the clusters or alveoli.
Each alveoli opens into mammary tubules. A mammary duct is formed when tubules emerging from each lobe join together. A mammary ampulla is formed when several mammary ducts merge. Mammary ampulla is further connected to the lactiferous duct through which milk is sucked out.