Difficulty: Hard

Average Score: 33%

Which of the following epithelial types is correctly matched with its major function?

Rationale

Simple columnar epithelium's major function is secretion or absorption.

This type of epithelium is found in areas of the body where substances need to be absorbed (such as the small intestine) or secreted (like in glands). The cells are tall and cylindrical, which allows for a large surface area to facilitate these processes.

A (Simple squamous epithelium - secretion or absorption) YOUR ANSWER

Simple squamous epithelium is primarily involved in diffusion and filtration, not secretion or absorption. Its thin, flat cells provide a short path for substances to pass through, making it ideal for places like the walls of capillaries and the air sacs in lungs.

B (Stratified squamous epithelium - changes shape when stretched) YOUR ANSWER

Stratified squamous epithelium does not change shape when stretched. This characteristic is typical of transitional epithelium, which is found in areas like the bladder that need to expand and contract. Stratified squamous epithelium is designed to protect against wear and tear, and it is found in areas that experience a lot of friction, like the skin and the esophagus.

C (Stratified squamous epithelium - diffusion) YOUR ANSWER

Stratified squamous epithelium is not primarily involved in diffusion. Its multiple layers of cells are designed to protect against abrasion, not facilitate the transfer of substances. As mentioned before, this type of epithelium is found in areas like the skin and the esophagus.

D (Simple columnar epithelium - secretion or absorption) CORRECT

Simple columnar epithelium is indeed involved in secretion and absorption. These tall, cylindrical cells are found in areas like the small intestine, where nutrients need to be absorbed, and in glands, where substances like mucus are secreted.

Conclusion

The major function of the simple columnar epithelium is secretion or absorption. The other choices—simple squamous epithelium, stratified squamous epithelium—are not correctly matched with their functions. Simple squamous is involved in diffusion and filtration, while stratified squamous provides protection against abrasion. The ability to change shape when stretched is characteristic of transitional epithelium, not stratified squamous.

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