Question

Simple epithelium is
A) One cell thick
B) Two cell thick
C) Two or three cells thick
D) All are correct

Answer 1

Hint:Epithelial tissues are those that cover all body surfaces including the linings of body cavities and organs. The functions of these tissues are varied depending on the location, and include secretory, protective, excretory, and sensory roles.

Complete answer:
Depending on the shape of the cells epithelial tissue may be squamous, cuboidal, or columnar. And then they can form single layers of cells, or multiple layers. Epithelial tissue that is found in one layer is said to be simple epithelium. So it can be simple columnar, simple cuboidal or simple squamous epithelium. Option A is the correct answer.
The moment there is more than one layer, the tissue is said to be stratified. Even only two layers are sufficient for this classification. So option B and C are for stratified epithelium, which again can be any of the three cell types. Options B and C are thus incorrect.
Sometimes epithelium can be described as pseudostratified; this is when the cells are arranged in such a way that they appear to be two layers, even though there is only one. This is seen in the lungs. Transitional epithelium is that which has cells of different shapes in each layer and this can easily be stretched while maintaining its integrity.

Hence the correct answer is option ‘A’.

Note:The lining of our intestines which is important for digestion and absorption consists of simple columnar epithelium along with glandular epithelium which will have cuboidal epithelial cells in it.