Tight junctions are specialized structures that form a barrier between adjacent cells, preventing substances from passing between them. They are made up of proteins that bind cells tightly together, creating a seal that is impermeable to most molecules.
Tight junctions are found in many different tissues and organs throughout the body, including the lining of the digestive tract, blood vessels, and the skin. They are also present in the blood-brain barrier, which helps regulate the movement of substances into and out of the brain.
The main function of tight junctions is to maintain the integrity of the barrier between cells. This helps to control the movement of substances, such as nutrients and waste products, between different parts of the body. Tight junctions also play a role in cell signaling and communication.
Tight junctions are different from other types of cell junctions, such as gap junctions and desmosomes, in that they create a complete seal between cells. This means that substances cannot pass between cells, whereas other types of junctions allow for limited movement of molecules.
If tight junctions are damaged or not functioning properly, it can lead to a disruption in the barrier between cells. This can result in increased permeability, allowing harmful substances to pass through and potentially causing inflammation or disease. Some diseases, such as inflammatory bowel disease, have been linked to dysfunction of tight junctions.
