What is the function of immune system?

1. Defense Against Infections:

- The immune system's primary function is to protect the body against infections caused by pathogens such as viruses, bacteria, fungi, and parasites.

- It recognizes and neutralizes these harmful agents, preventing or eliminating infections and diseases.

2. Recognition of Self vs. Non-Self:

- The immune system distinguishes between the body's own cells (self) and foreign substances (non-self). This ability ensures that the immune response is directed only against non-self entities and avoids attacking the body's own tissues.

3. Innate Immunity:

- The innate immune system provides an immediate but non-specific defense against pathogens.

- It includes physical barriers like skin and mucous membranes, as well as cellular components such as macrophages, neutrophils, and natural killer (NK) cells that recognize and eliminate pathogens without prior exposure.

4. Adaptive Immunity:

- The adaptive immune system mounts a specific and targeted immune response against pathogens that have breached innate immunity.

- It involves the activation and proliferation of lymphocytes (T cells and B cells) that can recognize specific pathogens and produce antibodies to neutralize them.

- This response also provides immunological memory, allowing for a faster and more effective response upon subsequent encounters with the same pathogen.

5. Antibody Production:

- B cells produce antibodies that bind to specific antigens (molecules on the surface of pathogens).

- Antibodies neutralize the pathogens, making them more susceptible to destruction by other immune cells.

6. Cell-Mediated Immunity:

- T cells play a crucial role in cell-mediated immunity, directly attacking and destroying infected cells or abnormal cells within the body, including cancerous cells.

7. Regulation and Balance:

- The immune system is tightly regulated to ensure an appropriate and balanced response.

- Regulatory mechanisms prevent excessive immune reactions (autoimmunity) that can damage the body's own tissues.

8. Immune Surveillance:

- The immune system continuously monitors and scans the body for any potentially harmful changes, such as the emergence of cancerous cells.

- This surveillance ensures prompt detection and elimination of abnormal cells.

9. Immunological Memory:

- After an infection, memory cells are formed, enabling the immune system to respond more rapidly and efficiently to the same pathogen if encountered again.

- This is the basis for vaccination, where controlled exposure to weakened or inactivated pathogens induces immunological memory without causing disease.

10. Tissue Repair:

- The immune system also contributes to tissue repair and regeneration following an injury or infection.

- Immune cells release chemical signals that stimulate the growth and repair of damaged tissues.