Immune System Flashcards
(37 cards)
Immune System
The immune system is a complex network of cells, tissues, organs, and proteins that protects the body from disease.
Parts of the Immune System
The immune system protects the body from disease causing agents known as pathogens. Composed of innate defense and adaptive defense.
Innate defense
Nonspecific response to pathogens by the immune system.
Adaptive defense
A specific response by the immune system to a given pathogen.
Innate Immune System
A collection of nonspecific barriers and cellular responses that serve as an inborn first and second line of defense against pathogens. Has three lines of defense. First ( skin, mucus, secretions), keeps pathogens from entering body. Second, (phagocytes, specific proteins, inflammatory response) fights pathogens that have entered body. Third, adaptive immune system, Lymphocytes, such as B-cells and T-cells fight and retain memory of the pathogen.
Adaptive Immune System
A passive or active immunity in which antibodies to a particular antigen are present in the body. Lymphocytes such as B cells and various T cells fight the pathogen and retain memory of the specific pathogen.
B cells
Lymphocytes that mature in the bone marrow and make antibodies in response to antigens.
T cells
White blood cells that mature in the Thymus and participate in an immune response.
Functions of the Immune System
Immune system prevents entry of pathogens through presence of barriers, composed of skin, secretions( acids, enzymes, and salt). If barriers are breached Adaptive immune system specifically identifies , targets and remembers pathogen.
Function of Immune System with other Systems
Pathogens can enter body through openings of the digestive, urinary, reproductive systems, and injuries. Lymph system is critical to the functioning of the immune system because pathogens from the blood also circulate through the lymph. B cells and T cells reside in lymph nodes and are activated when pathogen is encountered.
The Innate Immune System 1st Line of defense
A series of nonspecific barriers, physical, cellular, and soluble components impede pathogens. External barriers are the skin, mucous secretions, chemical barriers (low pH, salt, enzymes, and commensal microrganisms).
Innate Immune System 2nd line of defense
If barrier is breached 2nd line of defense is activated. Ex: cut in the skin cause inflammatory response, histamines are released increasing blood flow and phagocytes to the area, which destroy bacteria. Interferons proteins that that interfere with production of viruses. Fever also speeds up immune response. Antimicrobial peptides and “Natural Killer” Lymphocytes attack host cells that harbor intracellular pathogens.
Adaptive Immune System I
Adaptive immune system has two general responses to specific pathogens: cellular or humoral. Cellular reponse destroys infected cell. Humoral response destroys pathogens found in the body fluids using antibodies secreted by B cells..
Adaptive Immune System II
Responds by remembering signature molecules called “antigens” from pathogens to which the body has previously been exposed. Functional cells are Lymphocytes called “T cells” and “B cells”.
Adaptive Immune System III
Antigen-presenting cells (APCs) such as macrophages digest pathogens and present the pathogen antigen to “helper” T cells. Depending on the type of antigen to “helper” T cells , either a B cell or cytotoxic T cell is activated. Helper T Cell produce cytokines to activate Cytotoxic T cell. Cytotoxic T cell destroys pathogen based on antigen.
Adaptive Immune System IV
Helper T cell can also activate B cells in response to a specific antigen. Induce B cell to multiply rapidly into “plasma” cells. Plasma cells produce a large amount of antibodies that bind to antigen. When antigen appears again in the body memory cells will have memory of antigen and produce specific antibody against the antigen.
Passive and Active Immunity I
Passive and Active Immunity are two ways to protect the body through either passive introduction of antibodies as a protective agent or its active production by the body. both passive and active immunity can be induced artifically. Vaccinations introduce antigens, which are weakend or killed to elicit immune response. Passive immunity introduces antibodies from another source that can rapidly neutralize toxins. Ex: Rapid treatment for a snakebite is passive immunity.
Passive and Active Immunity II
Many diseases are caused by malfunction of the immune system. Underactivity immune system like AIDS is caused by Human Immunodeficiency Virus (HIV), which infects helper T cells and prevents them from activating Cytotoxic T Cells and B Cells and prevents adaptive immune system from operating.
Passive and Active Immunity III
An Overactive Immune System can result in allergy symptoms, such as sneezing and mucus secretion. Autoimmune Diseases, Diabetes, Rheumatoid Arthritis, and Multiple Sclerosis are all from immune system mistakenly targeting a host molecule as a foreign antigen.
Immune System and Other Body Systems
Immune System works hand in hand with other body systems to transport immune cells, signaling molecules and antibodies throughout the body. Ex: Circulatory system transports white blood cells throughout the body. Lymphatic system produces white blood cells or lymphocytes. Vessels in the lymph system drain fluid from body tissues and deliver foreign material to lymph nodes to be processed by lymphocytes. Red bone marrow, found in many bones of the skeletal system also produce white blood cells. Integumentary system skin is first line of defense.
Commensal Microorganism
Microscopic organisms that live in or on the human body without causing it harm.
Histamine
A white blood cell secretion that triggers capillary permeability.
Interferons
Proteins secreted by Leukocytes when they are infected with viruses.
Antimicrobial
A substance that kills or inhibits growth of microorganisms with minimal damage to the host.
