Answer:
Tight junctions
Explanation:
Tight junctions are present in epithelial cells such as in the mucosal membrane of the digestive tract and are formed by the network of claudins, occludins and junctions adhesion proteins. They control the movement of molecules and ions through the cell spaces such as by preventing the leakage of water and solutes. So they provide the more controlled transport like the molecules have to enter the cell in order to cross it by osmosis, diffusion or active transport. They may also serve by forming the leaky channels for the movement of small molecules and movement of integral membrane proteins can also be blocked by them between the basolateral and apical surface of the cell.
They can be divided into types tight epithelia that have tight junction and blocks most of the movement and leaky epithelia that have less tight junctions and allows a little bit greater movement of molecules.
Desmosomes are found in epidermis and cardiac muscles formed by protein plaque and provide great adhesion between cells.
There is a gap present between cell in gap junction and in muscle and nerve they allow impulse to spread rapidly.
