Question

A histologist would describe the layered , flat , scaly epithelium of human skin as
A. Simple squamous
B. Stratified squamous
C. Stratified columnar
D. Pseudostratified cuboidal

Answer 1

Hint:- A group of cells in which cells are similar in structure, function, and origin is called tissue. Based on function and structure tissues are of four types namely - Epithelial tissue, connective tissue, muscular tissue, and nervous tissue. Out of these, the first formed tissue during embryonic development is the epithelial tissue.

Complete step-by-step solution:-
● Epithelial tissue is the tissue that grows upon another tissue (underlying connective tissue).
● It is the only tissue in which cells are always arranged in a uniform layer.
● Based on the number of layers of cells, epithelial tissue is divided into two major groups namely
- Simple epithelium and Compound epithelium.
● Simple epithelial tissue is composed of a single layer of cells whereas compound epithelial tissue
is composed of two or more than two layers of cells.
● The major function of compound epithelial tissue is to protect against chemical and mechanical
stresses. It is further of two types namely - transitional epithelium and stratified epithelium.
● The stratified epithelium is of three types - stratified squamous, stratified cuboidal, and
stratified columnar based on the shape of the innermost layer of cells.
● If the keratin protein layer is present over the outer layer of stratified squamous, it is called a
keratinized stratified squamous epithelium and if not then called as non - keratinized stratified
squamous epithelium.
● Skin is the most common example of keratinized stratified squamous epithelium.
● It is multilayered and consists of flat squamous cells so categorized under stratified squamous
epithelium and due to the presence of the keratin layer, it becomes dead so it is keratinized
stratified squamous epithelium.
Thus the correct answer is option B.

Note:- Human skin is scaly in nature and is considered dead as it is covered by keratin protein that makes it dead. As the skin is dead, it forms the line of defense against pathogens because they are not able to grow on dead skin. Also, the skin contains pigments that provide specific colouration to the body.