All of the following are components of White pulp of spleen, except:
**Question:** All of the following are components of White pulp of spleen, except:
A. Periarterial lymphoid sheath (PALS)
B. Red pulp
C. Sinusoids
D. Marginal zone (MZ)
**Core Concept:**
The spleen is an essential immune organ that plays a crucial role in filtering blood, producing and storing red blood cells, and supporting the immune system. The spleen has two main regions: the white pulp and the red pulp. The white pulp, further divided into the periarteriolar lymphoid sheaths (PALS), marginal zone (MZ), and sinusoids, is responsible for the initiation of immune responses.
**Why the Correct Answer is Right:**
The correct answer is **B. Red pulp**. The red pulp is the primary region of the spleen responsible for blood filtration, red blood cell production, and storage. It does not contain any of the components found in the white pulp.
**Why Each Wrong Option is Incorrect:**
**A. Periarteriolar lymphoid sheath (PALS)**: PALS is a component of the white pulp, specifically surrounding the splenic arterioles. It is involved in the activation and maturation of lymphocytes, which are crucial for immune responses.
**C. Sinusoids**: Sinusoids are the blood vessels in the spleen that facilitate blood filtration and provide a site for the interaction between red blood cells and macrophages. They are part of the red pulp, not the white pulp.
**D. Marginal zone (MZ)**: MZ is another component of the white pulp, responsible for the initial recognition and activation of antibodies and complement proteins.
**Clinical Pearl:**
The spleen serves as a vital immune organ, containing various regions and components that facilitate immune responses. Understanding the different regions and their functions is essential for understanding the spleen's role in immune defense and maintaining overall health.
**Correct Answer:** None of the options B, C, and D are correct, as they are all components of the white pulp of the spleen. Option A (Periarteriolar lymphoid sheath) is the correct answer as it is a component of the red pulp, not the white pulp.