Generally, epithelial cell layers are responsible for separating two fluids. For example, the epithelium of blood vessels in animals separates the blood from the interstitial fluid. What characteristic would you expect to see in an epithelium that was specialised for passive diffusion of materials from one fluid to another?
A) a single layer of flattened cells
B) many layers of cells stacked together
C) large, cube-shaped cells
D) loosely connected cells surrounded by an extracellular matrix

Question

Quizplus · Accepted Answer

A single layer of flattened cells would allow for efficient and easy diffusion of materials between the two fluids. The flattened shape would increase surface area for diffusion, while a single layer would minimize the distance that molecules have to travel between the two fluids. Many layers of cells stacked together or large, cube-shaped cells would both create barriers to diffusion. Loosely connected cells surrounded by an extracellular matrix would not provide a tightly regulated barrier for selective diffusion.

Generally, Epithelial Cell Layers Are Responsible for Separating Two Fluids