A&P 2 University Of Memphis -A&P 2 - Immune System questions with answers

A&P 2 University Of Memphis -A&P 2 - Immune System questions with answersExplain the role of antigen-presenting cells (APCs) in the immune system. - correct answer - necessary to stimulate T cells as part of the immune response - ingest the pathogen, digest it and then display its antigens on the surface along with and MHC (major histocompatibility complex) antigen that identifies the cell as self Define the term: pathogen. - correct answer Any such agent that is capable of causing human disease Describe the many forms of nonspecific defense that provide protection against a wide range of pathogens, including physical barriers, leukocytes, macrophages, antimicrobial proteins, fever and inflammation. - correct answer - non-specific defense - defenses that are active against a wide variety of pathogens and are present at birth 1) physical barriers - 1st line of defense - skin and mucous membrane where epithelial tissues provide a physical barrier that resists the penetration of microorganisms and other pathogens from the environment 2) Leukocytes - 2nd line of defense - neutrophils, eosinophils, basophils, lymphocytes, monocytes macrophages - wander the tissues or exist as fixed dendritic cells in certain tissues, destroying bacteria and other pathogens by phagocytosis Describe the functions of cytokines, interferons and complement proteins in the body's nonspecific defense system. - correct answer - Cytokines - small proteins secreted by leukocytes, mast cells and other cells that act in endocrine or paracrine fashion to regulate activity of multiple cells that participate in the defense against pathogens - interferons - cytokine that are produced and secreted by somatic cells that have been infected by a virus; stimulate neighboring cells to produce antiviral proteins that inhibit the replication DNA within the cell. They also activate macrophages and NK cells to destroy infected cells - complement proteins - 20 β globulins that are always present in the plasma but only activated by the presence of a pathogen Describe the phases of inflammation that account for its role as a nonspecific defense response. - correct answer 1) Vasodilation of local vessel - leads to increased blood flow to the damaged tissue (hyperemia) that permits increased recruitment of cells and delivery of inflammatory chemical to the area