🏥 USMLE Exam Prep

In epithelia, which type of cell junction is primarily responsible for preventing paracellular movement of substances, forming a tight seal between adjacent cells?

A Desmosome
B Gap junction
C Hemidesmosome
D Tight junction

✓ Correct Answer: Option D

Tight junctions (zonula occludens) are crucial for establishing an impermeable barrier between epithelial cells, regulating the passage of molecules through the paracellular space and maintaining cell polarity.

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