Final answer:
The statement is true; both allergies and autoimmune diseases stem from hyperactive immune responses. The immune system is a complex network, involving organs, cells, and processes. Allergies involve overreaction to benign substances, whereas autoimmune diseases entail attacking self tissues.
Step-by-step explanation:
The statement that "allergies and autoimmune diseases both result from an over-reactive immune system" is true. These conditions are indeed similar in that they are characterized by an improper immune response. Allergies occur when the immune system erroneously identifies harmless substances, such as pollen or pet dander, as threats and mounts an unnecessary and often exaggerated response to them. In contrast, autoimmune diseases arise when the immune system mistakenly attacks the body's own healthy cells and tissues, perceiving them as foreign invaders.
The immune system is not confined to a specific organ or tissue but is a complex network that encompasses organs, cells, and proteins. It includes primary lymphoid organs like the bone marrow and thymus, where lymphocytes mature, and secondary lymphoid organs where immune responses are mounted. Lymphocytes, which include T cells and B cells, are a subset of white blood cells or leukocytes, and are key players in the adaptive immune system. They have the unique ability to remember past infections, leading to a swift and potent response upon re-exposure.
Components of the immune system, such as phagocytes, are involved in innate immunity, a non-specific defense mechanism present from birth. Phagocytosis, a process in which certain immune cells engulf and destroy pathogens, is a part of this system. Finally, Major histocompatibility complex (MHC) proteins are not antibodies but rather molecules essential for the adaptive immune response that display antigens on the cell surface for recognition by T cells.