Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): The tubules of each mammary lobe join to form a lactiferous duct.
Reason (R): The mammary glands are paired structures (breasts) that contain glandular tissue and variable amount of fat.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A) is false but (R) is true.
Assertion (A): The tubules of each mammary lobe join to form a lactiferous duct. — False. Milk passes through a chain of tubes. The alveoli open into mammary tubules, the tubules of each lobe join to form a mammary duct, several mammary ducts join to form the mammary ampulla, and only the ampulla is connected to the lactiferous duct. So the tubules of a lobe form a mammary duct, not a lactiferous duct.
Reason (R): The mammary glands are paired structures (breasts) that contain glandular tissue and variable amount of fat. — True. This is how the book describes the mammary glands. The glandular tissue of each breast is divided into mammary lobes with clusters of alveoli, whose cells secrete milk.
A is false and R is true.
NCERT Extract:
The Female Reproductive System – “… 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.”
