Final answer:
Epithelial tissue acts as a barrier between the body's internal and external environments, mediating the selective transport of substances through tight junctions and other cellular arrangements to maintain homeostasis.
Step-by-step explanation:
Function of Epithelial Tissue in Substance Transport
One important function of epithelial tissue is to control and mediate the transport of substances between the internal and external body regions, as well as between different internal compartments.
Epithelial cells form large sheets, acting as a barrier and gatekeeper to regulate the permeability across this cellular layer.
This control extends to the lining of various body parts, including those exposed to the outside world, such as skin and mucous membranes, and those that line internal organs and cavities like the airways, digestive tract, and the endothelium of blood vessels.
The unique arrangements of junctional complexes (tight junctions, desmosomes, and gap junctions) in epithelial tissues ensure controlled transport and selective permeability, which are essential for maintaining homeostasis within the body.