Question

The inner lining of stomach, rectum and colon is made up of:
A. Simple squamous epithelium
B. Simple cuboidal epithelium
C. Simple columnar epithelium
D. Pseudostratified epithelium

Answer 1

Hint: In the multicellular organisms, a group of cells which are morphologically and physiologically similar perform a same type of function. These cells are called tissue. The cells of tissue work in a coordinated manner such that their outcome is the same. Various tissues align themselves and form an organ.

Complete answer:
The tissues arrange themselves in a manner such that they form an organ which is specialized to perform a designated function in the body. These organs may be stomach, kidneys, heart, brain etc. The structure of cells in the organs varies and depends on the type of function they perform. Therefore, the tissues are divided into four major groups, namely: epithelial tissue, connective tissue, muscular tissue and neural tissues.
The epithelial tissue is known as epithelium. Epithelial tissue lines the surface of the body parts. This tissue always has a free surface; either it faces the body fluid or outside environment. These have very little intercellular matrix and are compactly arranged. Epithelial tissues are further classified as simple or compound epithelium. Simple epithelium has a single layer of cells and acts as a covering for body cavities, ducts and tubes whereas the compound epithelium has two or more cell layers and performs the function of protection just like our skin.
The epithelial cells are modified into squamous, cuboidal and columnar on the basis of structural modifications.
> Squamous epithelium: These are made of a single, thin and flattened layer with irregular boundaries which perform the function of diffusion and are found in walls of blood vessels and alveoli.
> Cuboidal epithelium: It is made up of a single layer of cuboidal cells which perform the function of secretion and absorption. It is mainly found in ducts of glands and tubular parts of nephrons.
> Columnar epithelium: These cells are tall and slender which also perform the function of secretion and absorption. These cells line the stomach and intestinal walls.

Therefore, the correct answer for this question is simple columnar epithelium that is option C.

Note: If the columnar or cuboidal cells have cilia present on their free or open surface then these are called ciliated epithelium. Ciliated epithelium helps to move particles or mucus in a specific direction in its environment. These are found in the inner surface of hollow organs like fallopian tubes and bronchioles.