Biology the immune system study notes

Steps your body takes to protect you from pathogens How does you body recognize pathogens?

Biology the immune system study notes

Microbial Products Cells of the Immune System Cells of the immune system are associated with the lymphatic system of the body and its specialized cells.

Can writing about pain and secret feelings really help boost your body’s immune system? BBC Future investigates. When you're in the mood, it's a sure bet that the last thing on your mind is boosting your immune system or maintaining a healthy weight. Yet good sex offers those health benefits and more. The immune system consists of a network of diverse organs and tissue which vary structurally as well as functionally from each other. These organs remain spreaded throughout the body. Basically, immune system is a complex network of lymphoid organs, tissues and cells.

Lymphocytes of the lymphatic system are derived from stem cells of the bone marrow. These undifferentiated precursor cells proliferate throughout life and replenish the mature cells of the immune system. There are two major pathways for the differentiation of stem cells into immune cells.

B-lymphocytes are so named because in birds, they are formed in the bursa of Fabricius. The equivalent site in humans has not been identified but is believed to be the bone marrow.

Figure 1 An overview of the human immune system. The transformation of stem cells into B-lymphocytes and T-lymphocytes begins about the fifth month after fertilization, and a full set is complete a few months after birth. These cells then migrate to the lymphoid organs in the lymph nodes, spleen, tonsils, adenoids, and other organs of the lymphatic system.

To initiate the immune response, microorganisms are phagocytized and their antigens are processed in phagocytic cells such as macrophages.

The antigenic determinants are displayed on the surface of the phagocytic cells and presented to the appropriate B-lymphocytes and T-lymphocytes to provoke an immune response. According to this theory, small populations clones of lymphocytes bear receptors on their cell membranes. Production of these receptors is genetically determined.

On B-lymphocytes, the receptors consist of antibody molecules, while on T-lymphocytes, they are clusters of amino acids. When lymphocytes encounter an antigenic determinant on the surface of a macrophage, their receptors match with the antigenic determinant and a stimulation follows.

Biology the immune system study notes

The clonal selection theory suggests that B-lymphocytes and T-lymphocytes exist for all antigenic determinants even before contact with an antigen is made.

The theory also says that antigenic determinants stimulate the lymphocytes to endow their progeny with identical specificity. Two general types of immunity exist for specific resistance to disease.

BBC - Future - The puzzling way that writing heals the body

They are antibody-mediated humoral immunity, centered in B-lymphocytes, and cell-mediated immunity, centered in T-lymphocytes.A Complex Business. In a complex adaptive system, local events and interactions among the “agents,” whether ants, trees, or people, can cascade and reshape the entire system—a property.

The Immune System chapter of this Campbell Biology Companion Course helps students learn the essential lessons associated with the immune system.

Steps of Response. First on the scene are the phagocytes like macrophages. Then the immune system send in two different lymphocytes (white blood cells that defend the body against foreign substances).


The First Year. Upon arriving at Texas A&M, we help you get acclimated to life in College Station and in the Department of Biology. You will meet your fellow entering students, who will undoubtedly be a source of friendship and moral support during graduate school and beyond. Discussion of the power of laughter and positive emotions to exert a healing influence via the immune system, including curing ‚incurable' disease and cancer.

The lymphatic system is part of the circulatory system but, instead of blood, it carries lymph — a clear liquid that ferries immune cells and rids the body of toxins and waste.


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Graduate Programs – Texas A&M Department of Biology