Which structures of the mammary glands are affected by the hormone progesterone?

Which structures of the mammary glands are affected by the hormone progesterone?

• A. Lactiferous Ducts
• B. Acinar Structures
• C. Nipple Areola Complex
• D. Stroma

Answer: (B)

The acinar structures of the mammary glands are significantly influenced by the hormone progesterone. Progesterone plays a vital role in the development and functioning of the mammary glands, particularly during pregnancy. It promotes the growth and differentiation of the acinar cells, which are responsible for milk production. These acini are the terminal units of the mammary glands, where milk is synthesized and stored.

During the menstrual cycle and particularly in the proliferative phase, progesterone levels rise, which leads to changes in the mammary glands to prepare them for potential lactation. This development includes the proliferation of acinar cells and the formation of lobules, making the breast tissue suitable for milk production.

Other structures mentioned, like the lactiferous ducts, the nipple-areola complex, and the stroma, may also be influenced by hormonal changes, but they are not as directly involved in milk production and modification as the acinar structures. Thus, it's the acinar structures that showcase the most significant hormonal response to progesterone during the preparation for lactation.