Question

Which of the following make the posterior surface of the tongue rough?
A. Papillae
B. Lymphoid nodule
C. Receptor cells
D. None of the above

Answer 1

Hint: The tongue is a voluntary muscle and glandular structure that occupies the floor of the mouth. It is attached to the floor of the mouth by a fold called the frenulum of the tongue. An inverted V-shaped sulcus called a terminal sulcus divides the upper surface of the tongue into the anterior and posterior part.

Complete answer:
Let's first learn about the anterior and posterior surface of the tongue.
The human tongue is divided into the anterior and posterior sections of the terminal groove, which is a V-shaped groove. The tip of the terminal groove is characterized by a blind opening, that is, the opening of the appendix, which is the remnant of the middle diverticulum of the thyroid early in embryonic development. The front lip is the visible part, which is at the front and is about two thirds the length of the tongue. The posterior pharynx is the part closest to the neck, approximately one third of its length. These parts differ in their embryological development and nerve supply.
To answer the question let’s first of all understand about all the options given above
Papillae: Papillae are small projections of the mucous membrane and are as follows: the mucous membrane covering the top of the tongue is thrown into several projections called the lingual papillae on the front two thirds of the tongue. The three types of papillae are: fungiform filiform, circumvallate
Lymphoid nodule: These are located at the root of the tongue behind the circulatory papillae. There are wide-necked crypts that are surrounded by lymphoid tissue. Each crypt is lined with stratified squamous epithelium. Like the tonsils, lymph tissue contains lymph nodes with germinal centres and canals from several mucosal glands that are exposed on the surface or in crypts. Its secretions wash away microorganisms, making tonsils of this type less susceptible to infection.
Receptor cells: Taste receptors contain taste receptor cells, also called taste buds. Taste receptors are located around tiny structures called papillae, which are located on the top of the tongue.
Hence, from the above points it's clear that the correct option is (B).

Note:
Like other lymphatic tissues, the function of the lingual tonsils is to prevent infection. These tonsils contain B and T lymphocytes, which are activated when harmful bacteria and viruses come in contact with the tonsils. In lymphocytes, they kill pathogens by producing antibodies against them, whereas T lymphocytes kill them directly by ingesting them or indirectly by stimulating other cells in the immune system.