## **Core Concept**
The spleen is an organ that plays a critical role in the immune system, acting as a filter for the blood and storing red blood cells and lymphocytes. It consists of two main types of tissue: white pulp and red pulp. The white pulp is composed of lymphatic tissue, while the red pulp is involved in filtering the blood.

## **Why the Correct Answer is Right**
The correct answer, , is right because the spleen indeed consists of white pulp, red pulp, and the splenic capsule, but it does not contain **gastric mucosa**. The white pulp is composed of lymphoid tissue that surrounds the splenic arteries, and the red pulp is involved in filtering the blood. The splenic capsule is a fibrous layer that surrounds the spleen.

## **Why Each Wrong Option is Incorrect**
* **Option A:** - This option is incorrect because the spleen does contain **white pulp**, which is a part of the lymphoid tissue.
* **Option B:** - This option is incorrect because the spleen does contain **red pulp**, which is involved in filtering the blood.
* **Option D:** - This option is incorrect because the spleen is indeed covered by a **splenic capsule**, which is a fibrous layer.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that the spleen's main functions include filtering the blood, storing red blood cells, and housing lymphocytes. Damage to the spleen can lead to a risk of infection, particularly from encapsulated bacteria.

## **Correct Answer:** . Gastric mucosa