Question

The epithelium found in the inner linings of the stomach and intestine is
(a) Columnar
(b) Squamous
(c) Stratified
(d) Pseudostratified

Answer 1

Hint: It is a type of simple epithelium, having absorption and secretion properties are present in the inner lining of the stomach and intestines and other organs of the digestive tract that helps in absorption.

Complete answer:
The simple columnar epithelium is a type of simple epithelium tissue. It is formed by a single layer of cells attached to a basement membrane. The cells are taller and are packed in a compact manner. They have characteristic properties of absorption of food particles and secretion of products like enzymes, mucus, etc. The inner lining of the stomach also called tunica mucosa has columnar cells that secrete mucus. This mucus helps in protecting the walls of the stomach from the acidic activity of hydrochloric acid (HCl). The innermost layer of the intestine, tunica mucosa, has simple columnar epithelium with numerous goblet cells present in between them.
- columnar epithelia are also found in the gallbladder.
- Goblet cells are modified columnar cells having mucinogen granules in their cytoplasm.
- They form finger- like projections known as villi which play an important role in the absorption of digested food. They also increase the surface area of the walls to provide a wider space for better absorption of food.
- The secretion of intestinal enzymes from the tunica mucosa and submucosa helps in the breakdown of proteins, carbohydrates, and fats into basic amino acids, monosaccharides, and triglycerides, respectively.
- The columnar epithelium present in tunica mucosa forms grooves of tubular glands known as Crypts of Lieberkühn.
- Enzymes and mucus are secreted from the tubular gland.
So, the correct answer is ‘(a) Columnar’.

Note: Goblet cells are unicellular mucus- secreting glands present in between the layers of simple columnar epithelium. Squamous epithelium is a single- layered flat cell that is attached to the basement membrane and helps in the transportation of minute particles through diffusion and filtration. When the layer of the epithelium is made up of several layers then it is called a stratified epithelium. The pseudostratified epithelium is a single layer of the cell but is arranged as multi-layered.