Questions: Which gives epithelial cells the ability to withstand significant mechanical stress? Occludins Tight junctions Connexons Desmosomes Gap junctions

The answer is the fourth one: Desmosomes.

Explanation for each option:

1. Occludins: These are proteins associated with tight junctions, which primarily function to create a barrier to prevent the passage of molecules between cells. They do not provide significant mechanical strength.

2. Tight junctions: These junctions seal cells together in an epithelial sheet to prevent leakage of molecules between them. While they contribute to the integrity of the epithelial layer, they are not primarily responsible for withstanding mechanical stress.

3. Connexons: These are components of gap junctions, which allow for communication between cells by permitting the passage of ions and small molecules. They do not provide mechanical strength.

4. Desmosomes: These are specialized structures that provide strong adhesion between cells, allowing epithelial tissues to withstand mechanical stress. They are crucial for maintaining the structural integrity of tissues that experience significant mechanical forces.

5. Gap junctions: These junctions facilitate communication between cells but do not contribute to mechanical strength.

In summary, desmosomes are the structures that give epithelial cells the ability to withstand significant mechanical stress.