N104: Essentials of Nursing Care - Health Safety

N104: Essentials of Nursing Care – Health Safety Study Guide Specific Immune Responses The specific immune response is antigen-specific and requires the recognition of specific “non- self” antigens during a process called the antigen presentation. Antigen specificity allows for the generation of a response tailored to a specific pathogen or pathogen-infected cell. The ability tomount a tailored response is maintained in the body and should a pathogen infect the body more than once, specific memory cells are used to quickly eliminate it. The cells of the immune system are special types of leukocytes, called lymphocytes. The major types of lymphocytes are B cells and T cells and are derived from stem cells in the bone marrow. B cells are involved in the humoral immune response, whereas T cells are involved in the cell-mediated immune response. Both B cells and T cells carry receptor molecules that recognize specific targets. T cells recognize a “non-self” target, such as a pathogen, only after antigens (small fragments of the pathogen) have been processed and presented in combination with a “self” receptor. In contrast, the B cell antigen-specific receptor is an antibody molecule on the B cell surface,which recognizes whole pathogens without any need for antigen processing. Each B cell expresses a different antibody, so the complete set of B cell antigen receptors represent all the antibodies that the body canmanufacture. Acquired immunity is the process of vaccination against specific diseases. Vaccination is done in three ways: • Vaccination with toxins that have been treated so that this toxic nature has been destroyed. The tetanus vaccination is an example of this kind. • Vaccination with dead organisms that still have their antigen but are not capable of causing disease. The pertussis vaccination is an example of this kind. • Vaccination with live attenuated organisms, which are not capable of causing disease but are still carrying the specific antigen. The measles vaccination is an example of this kind. Nonspecific Immune Defense In contrast to the specific immune responses, the body also has an array of protective mechanisms that are not dependent on previous exposure to the antigen. • Intact skin is recognized as the body's first line of defense against the infections. Skin acts as a physical barrier and the sebum produced by the skin contains fatty acids that will kill some bacteria. The normal skin flora can compete with pathogens and keep the pathogens under control. • Mucous membranes produce mucous that traps infectious agents and inhibits growth. • Many of the fluids in the body are naturally acidic; this acidity can inhibit the growth of the pathogens. • Elimination of toxins occurs with urination and defecation. • Reflexes such as tearing, sneezing, and coughing can physically remove antigens that might otherwise cause infection. Stages in the Infectious Process • Stage one, incubation: The incubation period is the time between the entry of the organism

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