Nursing Entrance Exam

7.5.3 Common Diseases and Disorders Listed below are the three common disorders of the immune system. 1. Immunodeficiency: The most widely known, due in part to the human immunodeficiency virus, or HIV, the virus that causes AIDS. An immunodeficiency occurs when certain components of the person’s immune system become inactive. Although we tend to think of HIV when we think of immunodeficiency, in reality, it is common for an elderly person’s immune system to start declining in their later years, which is also a type of immunodeficiency. 2. Autoimmunity: The term for when the body’s immune system does not correctly distinguish between non-self and self, thus attacking part of the person’s own body. Normally, antibodies and T cells respond with what is called “self” peptides. With autoimmunity, this process is disrupted. 3. Hypersensitivity: A response of the immune system that damages bodily tissues. There are four classes of hypersensitivity. Type 1 is an immediate reaction that is usually associated with allergy. Type 2 happens when antigens and antibodies bind together on the person’s own cells, thus marking them for destruction. Type 3 is triggered when aggregations of antigens, IgG and IgM antibodies, and complements are deposited in specific tissues. And type 4, which takes two to three days to develop, involves infectious diseases, but can also involve skin contact (poison ivy is an example). Reactions can be helped by monocytes, T cells, and macrophages.

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