The immune system has evolved to protect animals and humans from invading pathogenic microorganisms and cancer. The function of immune system is to generate different variety of cells and specific molecules capable of specifically recognizing and eliminating endless list of a variety of foreign invaders.
The immune response developed by immune system can be broadly divided two related activities—recognition and response. Immune recognition is remarkable for its specificity. Once a foreign organism has been recognized, the immune system employs a variety of cells and molecules to display an appropriate response, called an effector response, to eliminate or neutralize the organism.
Upon repeated exposure to the same organism immune system induces memory response which is characterized by rapid and increased immune reaction helping to eliminate the foreign pathogen.
Organs and Cells of the Immune System
Bone Marrow
All the specialized cells of the immune system are formed in the bone marrow, where they mature. When they are fully mature they move into the blood stream where they do their work.
Thymus
This small but important organ is where lymphocyte precursors become thymocytes, which in turn mature into T-cells. In addition, the thymus actually chooses which T-cells are best suited for the immune system. The remaining ones are eliminated by the body, assuring a healthy, effective immunity.
Spleen
You can think of the spleen as a filter for the blood. It catches foreign material in the blood and activates different types of immune system cells.
Lymph Nodes
The lymph nodes filter foreign material from the lymph fluid. Fluid that drains from various tissues in the body collects in the lymph system and passes through the nodes, being filtered as it passes.
Types of Immune Response by Immune System
Immunity as component of immune system is represented as state of protection from infectious disease and has two components based on specificity. One component is referred as innate and second is termed as adaptive immunity.
Innate immunity refers to first line defense against infection, and the components are present before the onset of infection and comprise disease-resistant mechanism, which are generally not specific to particular pathogen.
It can include cellular and molecular components which can recognize the classes of molecules mainly based on chemical nature. Innate immunity is comprised of 4 types of defensive barriers, anatomic, physiologic, phagocytic, and inflammatory.
Adaptive and Innate Immunity
Adaptive Immunity is known for recognizing and selective elimination of foreign microorganisms and molecules. The process is known for its specificity and has the following features.
Antigenic specificity
Diversity
Immunologic Memory
Self/non-self recognition
Differences between Innate and Adaptive
Adaptive and innate immunity do not operate independently, but in fact they work in a highly interactive and cooperative system resulting in production of combined response, which is more effective than independently produced by individually.
Small differences do exist in both branches of defense mechanism: An innate immunity is characterized by small response time (minutes to hours), limited specificity and similar response to primary infection. Adaptive immunity differ out by large response time (Days), highly fixed specificity, and rapid response to primary infection.
Differences between Innate and Adaptive
Adaptive and innate immunity do not operate independently, but in fact they work in a highly interactive and cooperative system resulting in production of combined response, which is more effective than independently produced by individually.
Small differences do exist in both branches of defense mechanism: An innate immunity is characterized by small response time (minutes to hours), limited specificity and similar response to primary infection. Adaptive immunity differ out by large response time (Days), highly fixed specificity, and rapid response to primary infection.
