Microvilli of epithelium cells

Options

A. Increase the surface area
B. protect the cells
C. Engulfs the foreign matter
D. Give movement of cells

Answer

### Step-by-Step Text Solution:

1. **Definition of Microvilli**: Microvilli are tiny, finger-like projections found on the surface of epithelial cells. They are extensions of the cell membrane and are composed of a core of actin filaments.

**Hint**: Remember that microvilli are not just random projections; they are specialized structures that enhance the cell's functionality.

2. **Characteristics of Microvilli**: Microvilli are non-motile and non-contractile. This means they do not move or change shape actively like some other cellular structures (e.g., cilia).

**Hint**: Focus on the fact that microvilli are stable structures that serve a specific purpose rather than being dynamic like cilia.

3. **Function of Microvilli**: The primary function of microvilli is to increase the surface area of the epithelial cells. This increased surface area is crucial for absorption and secretion processes.

**Hint**: Think about why increasing surface area is important—more area means more space for absorption of nutrients or other substances.

4. **Extent of Surface Area Increase**: Microvilli can increase the surface area of epithelial cells by approximately 20 times. This significant increase is vital for the efficiency of the cells, especially in organs like the intestines where absorption is key.

**Hint**: Consider the implications of a larger surface area in terms of efficiency—how does this relate to the functions of the organs where microvilli are found?

5. **Comparison with Other Structures**: Unlike cilia, which are involved in movement and can propel substances across the epithelial surface, microvilli do not provide movement. Instead, they are primarily involved in enhancing absorption.

**Hint**: Distinguish between the roles of microvilli and cilia—this will help clarify their functions in the context of epithelial tissue.

### Summary:
Microvilli are non-motile, non-contractile projections that increase the surface area of epithelial cells by about 20 times, enhancing their ability to absorb nutrients and other substances. They are distinct from cilia, which are involved in movement.