**Question:** Gland of Moll are modification of which gland?

A. Thymus
B. Pancreas
C. Parathyroid
D. Salivary gland

**Core Concept:** Gland of Moll is a specialized type of lymphatic tissue found in the respiratory tract, primarily in the tonsils and adenoids. It plays a crucial role in the immune system by providing a first line of defense against inhaled pathogens.

**Why the Correct Answer is Right:** Gland of Moll is a modification of the thymus gland, which is the primary site of T cell development and maturation in the human body. These T cells then migrate to various lymphoid tissues, including the tonsils and adenoids, to provide a local immune response against inhaled pathogens.

**Why Each Wrong Option is Incorrect:**

A. Thymus: Although the gland of Moll shares some similarities with the thymus, it is a distinct entity in the respiratory tract, providing a local immune response against inhaled pathogens, while the thymus focuses on T cell development and maturation.

B. Pancreas: The pancreas is a vital endocrine and exocrine gland involved in blood glucose regulation, digestion, and nutrient absorption. It is not related to the immune system or mucosal immunity in the respiratory tract.

C. Parathyroid: The parathyroid glands are responsible for calcium homeostasis and phosphorus regulation, not immune function or mucosal immunity in the respiratory tract.

D. Salivary gland: Salivary glands primarily secrete saliva for digestion and lubrication of the mouth, not immune function or mucosal immunity in the respiratory tract.

**Clinical Pearl:** The understanding of gland of Moll's relationship with the thymus highlights the importance of local immune responses in various body sites, specifically in mucosal immunity, which is crucial in preventing infections and protecting the body against pathogens.

**Correct Answer:** A. Thymus

The correct answer is the thymus because the gland of Moll is a specialized lymphoid tissue that serves as a modification of the primary lymphoid organ, the thymus, which is responsible for T cell development and maturation. While both share similarities in terms of immune function, the gland of Moll is specifically adapted to provide a local immune response against inhaled pathogens in the respiratory tract, whereas the thymus is vital for the development of T cells in the body at large.