Desmosomes contain fine filamentous structures called :

Options

A. Tonofilaments
B. Stereocilia
C. Terminal Bars
D. Myosin

Answer

**Step-by-Step Solution:**

1. **Understanding Desmosomes:**
- Desmosomes are specialized structures in cell membranes that provide adhesion between cells, particularly in tissues that experience significant mechanical stress, such as epithelial tissues.

2. **Identifying the Fine Filamentous Structures:**
- The question asks for the fine filamentous structures contained within desmosomes. These structures play a crucial role in the function of desmosomes.

3. **Evaluating the Options:**
- **Option 1: Tonofilaments**
- Tonofilaments are indeed fine filamentous structures that are composed of keratin intermediate filaments. They are associated with desmosomes and help in anchoring the cells together.
- **Option 2: Stereocilia**
- Stereocilia are non-motile, hair-like structures found on the surface of certain cells, but they are not related to desmosomes.
- **Option 3: Terminal Bars**
- Terminal bars refer to junctional complexes in histology but do not specifically refer to the filamentous structures in desmosomes.
- **Option 4: Myosin**
- Myosin is a type of thick filament involved in muscle contraction and is not related to the structure of desmosomes.

4. **Conclusion:**
- After evaluating all options, the correct answer is **tonofilaments**, as they are the fine filamentous structures found in desmosomes.

**Final Answer:**
Desmosomes contain fine filamentous structures called **tonofilaments**.

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