Mammary Glands - Human Reproduction, Biology, Class 12

Introduction:
Mammary glands are specialized organs found in mammals, including humans, that are responsible for producing milk to nourish their offspring. These glands undergo significant modifications to fulfill their function and are derived from a specific type of gland.

Modification of Which Gland:
Mammary glands are modifications of sweat glands. They are a type of exocrine gland that has evolved to produce milk instead of sweat. The mammary gland develops from the embryonic mammary ridge, also known as the milk line, which extends from the armpit to the groin region.

Structure and Function:
Mammary glands are composed of lobes, which are further divided into lobules. Each lobule consists of clusters of milk-producing cells called alveoli. The alveoli are surrounded by myoepithelial cells that contract to expel milk from the gland.

The primary function of mammary glands is to produce, secrete, and deliver milk to nourish newborns. The milk is rich in essential nutrients, antibodies, and growth factors that support the growth and development of the offspring. The milk production is stimulated by the hormone prolactin, which is released from the pituitary gland.

Hormonal Regulation:
The development and function of mammary glands are regulated by various hormones. During puberty, estrogen and progesterone stimulate the growth and branching of the glandular tissue. These hormones also cause the deposition of adipose tissue in the breasts, contributing to their size and shape.

During pregnancy, high levels of estrogen and progesterone prepare the mammary glands for milk production. After childbirth, the hormone prolactin is released, initiating lactation. Prolactin stimulates the alveoli to produce milk, while the hormone oxytocin causes the contraction of myoepithelial cells, releasing the milk from the alveoli into the ducts and eventually to the nipple.

Conclusion:
In conclusion, mammary glands are modified sweat glands that have evolved to produce milk. They undergo significant changes during puberty, pregnancy, and lactation to fulfill their function. The hormonal regulation of mammary glands ensures the proper development and secretion of milk, providing essential nutrition to newborns.