What is the immune system made of?

Components of the Immune System:

1. Cells:

- White blood cells (leukocytes): Neutrophils, monocytes, eosinophils, basophils, lymphocytes (T cells, B cells, natural killer cells).

2. Organs:

- Thymus: Maturation site of T cells.

- Bone marrow: Production of all types of blood cells, including immune cells.

- Spleen: Filters and destroys old or defective blood cells, plays a role in immune responses.

- Lymph nodes: Trap and filter pathogens, contain immune cells.

- Peyer's patches: Specialized lymphoid tissue in the small intestine.

- Tonsils and adenoids: Protect against pathogens entering through the mouth and nose.

3. Antibodies and Proteins:

- Immunoglobulins (antibodies): Proteins produced by B cells to neutralize and remove specific antigens.

- Interferons: Proteins that inhibit virus replication and alert other cells to the presence of viruses.

- Cytokines: Proteins that regulate immune responses and communication between immune cells.

- Complement proteins: A group of proteins that work together to destroy pathogens.

4. Physical Barriers:

- Skin: Acts as a physical barrier to pathogens.

- Mucous membranes: Line the respiratory, digestive, and urogenital tracts, secreting mucus that traps pathogens.

- Tears, saliva, and stomach acid: Contain antimicrobial substances.

5. Microbiota:

- Beneficial bacteria, viruses, and fungi that reside on and within the body, providing protection against harmful pathogens.

These components work collectively to protect the body against infections, pathogens, and foreign substances.