A.
Tight junctions are cell junctions in areas that are subjected to great mechanical stress, such as the skin and heart muscles
Explanation:
They are also called exclusion junctions. This is because they form very tight junctions between adjacent cells such that only very small molecules, like ions, can pass in between the intercellular spaces of the cells. This is why they are found in regions where very little leakage is needed such as the heart -where blood could leak out during pumping- or the skin where foreign material cannot be allowed into the body.
They are also favorable in high stress regions because they bound cells together giving them structural integrity because they limit the movement of cells and their membrane intergral proteins.
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Answer:
C. junctions among epithelial cells lining the digestive tract
Explanation:
In a tight junction, a series of integral protein molecules (including occludins and claudins) in the plasma membranes of adjacent cells fuse together, forming an impermeable junction that encircles the cell. Tight junctions help prevent molecules from passing through the extracellular space between adjacent cells. For example, tight junctions between epithelial cells lining the digestive tract keep digestive enzymes and microorganisms in the intestine from seeping into the bloodstream.
