**Question:** The functions of myoepithelial cells may be:

A. Secretory
B. Contractile
C. Structural support
D. Both A and C

**Core Concept:** Myoepithelial cells are specialized cells found in the epithelium of certain glands, particularly salivary glands. They have unique functions that contribute to gland homeostasis and overall gland function.

**Why the Correct Answer is Right:** Myoepithelial cells are involved in maintaining gland homeostasis and performing specific tasks. They possess contractile and secretory capabilities, allowing them to:

1. **Option D (Both A and C):** Myoepithelial cells can secrete substances like mucus, enzymes, and ions, contributing to glandular secretion and maintaining gland homeostasis. They also contract when stimulated, allowing them to modulate glandular secretion and facilitate fluid transport within the gland.
2. **Option A (Secretory):** Besides their secretory functions, myoepithelial cells also contribute to gland homeostasis by producing and secreting various substances, such as mucous, enzymes, and ions. These secretions help regulate glandular function and maintain gland integrity.
3. **Option C (Structural support):** Although myoepithelial cells primarily focus on secretory and contractile functions, they also provide structural support to the gland epithelium. Their contractile actions help maintain gland shape, prevent gland collapse, and contribute to the overall structural integrity of the gland.

**Why Each Wrong Option is Incorrect:**

1. **Option B (Contractile only):** While contractile functions are important for myoepithelial cells, they also have secretory roles in maintaining gland homeostasis and structure. Including only contractile functions would be an oversimplification of their multifaceted roles.
2. **Option B (Secretory only):** Although myoepithelial cells secrete various substances, including mucus, enzymes, and ions, they also possess contractile properties. Overspecifying secretory functions would disregard their structural and regulatory roles in maintaining gland homeostasis and integrity.
3. **Option D (Neither):** Myoepithelial cells fulfil essential functions in gland homeostasis, structure, and secretion. Omitting either their secretory or contractile functions would not accurately represent their comprehensive role in glandular systems.

**Core Concept:** Myoepithelial cells are crucial components of glandular epithelia, playing a vital role in maintaining gland homeostasis, structure, and secretion. They contribute to glandular function by secreting various substances, contracting to modulate secretion, and providing structural support. Understanding these essential roles is essential for students studying glandular systems in medicine and related fields.