Question

Which of the following is not a component of immune system?

• A. Lymphocytes
• B. Plasma Proteins
• C. Red Blood Cells
• D. Bone Marrow

Hint:

The immune system is broadly categorized into:
- Lymphoid Organs: Bone marrow, Thymus, Spleen, Lymph nodes.
- Immune Cells: Lymphocytes, Monocytes, Macrophages, Neutrophils.
- Soluble Factors: Antibodies, Cytokines, Interferons.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The immune system is a biological structure consisting of many layers of defense that protect the body from diseases.
It includes various cells, tissues, organs, and soluble molecules that recognize and neutralize pathogens.
Step 2: Detailed Explanation:
Let us evaluate each of the given components:
1. Lymphocytes: These are essential white blood cells. B-lymphocytes produce antibodies for humoral immunity, and T-lymphocytes are responsible for cell-mediated immunity. They are the core cells of the immune system.
2. Plasma Proteins: Various proteins in the blood plasma, such as Immunoglobulins (antibodies) and the Complement system, are vital soluble components that help in identifying and destroying pathogens.
3. Bone Marrow: It is a primary lymphoid organ where all blood cells, including leukocytes (immune cells), are produced through hematopoiesis. It is also the site for B-cell maturation.
4. Red Blood Cells (Erythrocytes): These cells contain hemoglobin and are specialized for the transport of oxygen and carbon dioxide. While they are a part of the circulatory system, they do not participate directly in immune defense mechanisms.
Step 3: Final Answer:
Red Blood Cells are specialized for respiratory gas transport and do not constitute a functional component of the immune system.