Question

The cell junctions called tight, adhering and gap junctions are found in

• A. Muscular tissue
• B. Epithelial tissue
• C. Connective tissue
• D. Neural tissue

Answer 1

Answer: (B)

• In some tissues, like that of epithelia, the plasma membrane of adjacent cells are pressed together.
• Four kinds of such junctions are present in vertebrates as follows:

Tight junctions seal adjacent epithelial cells in a narrow band just beneath the apical surface (e.g., epithelia of the human lung).
Adherens junctions provide strong mechanical attachments between adjacent cells. They hold epithelial cells together.
Gap junctions are intracellular channels, which permit the free passage of the ions and the small molecules (e.g., the action potential in cardiac muscle flows from cell to cell through the heart providing the rhythmic contraction of the heartbeat.
Desmosomes are localized patches that hold two cells tightly together. (e.g., skin epithelia).