Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Myoepithelial cells force secretory product into duct system.
Reason (R) : Myoepithelial cells are well developed in sweat glands.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A).
• B. Both (A) and (R) are correct but (R) is NOT the correct explanation of (A).
• C. (A) is correct but (R) is not correct.
• D. (A) is not correct but (R) is correct.

Hint:

Myoepithelial cells are of ectodermal origin but possess functional properties of smooth muscle cells, making them unique "hybrid" cells in mammalian histology.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Myoepithelial cells are specialized contractile epithelial cells located between the secretory epithelial cells and the basement membrane of various exocrine glands.

Step 2: Detailed Explanation:
Let us analyze the correctness and relationship of both statements:
- Assertion (A):
Myoepithelial cells contain myofilaments (actin and myosin) similar to those in smooth muscle cells.
Upon nervous or hormonal stimulation, these cells contract, squeezing the secretory acini and forcing the synthesized secretory products out of the alveoli and into the duct system.
Therefore, Assertion (A) is correct.
- Reason (R):
Myoepithelial cells are indeed highly developed in exocrine glands such as mammary glands, salivary glands, and sweat glands (especially apocrine sweat glands) to facilitate secretion.
Therefore, Reason (R) is correct.
- Relationship between (A) and (R):
Although both statements are factually correct, the presence of myoepithelial cells in sweat glands does not explain the biological mechanism of how they force secretory products into the duct system.
The actual explanation for their contractile function is the presence of intracellular contractile proteins (actin, myosin, and cytokeratins) and hemidesmosomes that bind them to the extracellular matrix, allowing coordinated contraction.
Thus, (R) is not the correct explanation of (A).

Step 3: Final Answer:
The correct option is (B).