Choose the correct statements with respect to the mammary glands of the human female:
A. The alveoli, whose cells secrete milk, occur as clusters of cells within the mammary lobes.
B. The milk secreted by the cells of alveoli is stored in the cavities (lumens) of alveoli.
C. In each mammary lobe, the mammary tubules join to form a mammary ampulla.
D. The mammary ampulla is connected to the lactiferous duct through which milk is sucked out.
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A, B and D only
A mammary gland makes milk in small sacs and carries it out through a series of tubes. Small tubes join to form larger ones, so the passage becomes wider as milk moves towards the nipple.
Statement A: The alveoli, whose cells secrete milk, occur as clusters of cells within the mammary lobes. — True. The alveoli are the milk-making units. They lie in clusters inside each mammary lobe of the glandular tissue.
Statement B: The milk secreted by the cells of alveoli is stored in the cavities (lumens) of alveoli. — True. Milk is first held in the lumens of the alveoli. From there it passes into the mammary tubules.
Statement C: In each mammary lobe, the mammary tubules join to form a mammary ampulla. — False. The tubules of each lobe join to form a mammary duct, not an ampulla. The ampulla comes one step later, when several mammary ducts join to form this wider space.
Statement D: The mammary ampulla is connected to the lactiferous duct through which milk is sucked out. — True. The lactiferous duct is the last part of the path. It opens at the nipple, and milk leaves the gland through it during suckling.
NCERT Extract:
The Female Reproductive System – “… A functional mammary gland is characteristic of all female mammals. The mammary glands are paired structures (breasts) that contain glandular tissue and variable amount of fat. The glandular tissue of each breast is divided into 15-20 mammary lobes containing clusters of cells called alveoli (Figure 2.4). 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 lactiferous duct through which milk is sucked out.”
Figure 2.4 A diagrammatic sectional view of Mammary gland