BODY DEFENSES Flashcards
Two mechanisms that make up the immune system
Innate and Adaptive defense systems
specific resistance to disease
Immunity
True or False. Immune system is a functional system rather than an organ system in an anatomical sense
True
What is the first line of defense?
Surface membrane barriers
Forms mechanical barrier that prevents entry of pathogens and other harmful substances into the body
Intact skin
Skin secretions make epidermal surface acidic, which inhibits bacterial growth; sebum also contains bacteria-killing chemicals
Acid mantle
Provides resistance against acids, alkalis, and bacterial enzymes.
Keratin
Form mechanical barrier that prevents entry of pathogens
Intact Mucous Membranes
Traps microorganisms in respiratory and digestive tracts.
Mucus
Filter and trap microorganisms and other airborne particles in nasal passages.
Nasal hairs
Propel debris-laden mucus away from lower respiratory passages
Cilia
Contains concentrated hydrochloric acid and protein-digesting enzymes that destroy pathogens in the stomach
Gastric juice
Inhibits growth of bacteria and fungi in female reproductive tract.
Acid mantle of vagina
Continuously lubricate and cleanse eyes and oral cavity
Tears and Saliva
What is the second line of defense?
Cellular and Chemical defenses
Engulf and destroy pathogens that breach surface membrane barriers; macrophages also contribute to immune response.
Phagocytes
Promote cell lysis by direct cell attack against virus-infected or cancerous body cells; do not depend on specific antigen recognition
Natural Killer Cells
Prevents spread of injurious agents to adjacent tissues, disposes of pathogens and dead tissue cells, and promotes tissue repair
Inflammatory Response
Group of plasma proteins that lyses microorganisms, enhances phagocytosis by opsonization, and intensifies inflammatory response.
Complement
Proteins released by virus-infected cells that protect uninfected tissue cells from viral takeover; mobilize the immune system
Interferons
Normally acid pH inhibits bacterial growth; urine cleanses the lower urinary tract as it flushes from the body.
Fluids with acid pH
Systemic response triggered by pyrogens; high body temperature inhibits multiplication of bacteria and enhances body repair processes
Fever
What are the five lines of innate internal defense?
Phagocytes, NK cells, antimicrobial proteins, inflammation, and fever
the adaptive defense system recognizes and acts against particular foreign substances
Antigen specific
immunity is not restricted to the initial infection site
Systemic
the adaptive system defense system recognizes and mounts a stronger attack on previously encountered pathogens
Memory
antibody-mediated immunity
Humoral immunity
initial encounter with antigens. antigens will bind with the receptor of B cells where it will be activated.
Primary response
creates the antibodies during primary response
Plasma cells
remembers the antigen and prepares the body for future infection
Memory cells
more rapid response from the same antigen because the body was able to recognize it
Secondary response
type of humoral immunity where you are exposed to pathogens
Active
Natural or Artificial. Infection contact
Natural
Natural or Arftificial. Vaccines
Artificial
type or humoral immunity where you are not exposed but you are able to carry the antibodies needed
Passive
Natural or Artifical. Breastmilk
Natural
Natural or Artificial. Injected antibodies
Artificial
cell-mediated immunity
Cellular immunity
What is the third line of defense?
Adaptive defense system
develop immunocompetence in the thymus and overseen cell-mediated immunity
T cells
develop immunocompetence in bone marrow and provide humoral immunity
B cells
also referred to as immunoglobulins; constitute the gamma globulin part of blood proteins
Antibodies
are soluble proteins secreted by activated B cells or by their plasma-cell offspring in response to an antigen, and they are capable of binding specifically with that antigen
Antibodies
When bound to B cell membrane, serves as antigen receptor
IgM
Bathes and protects mucosal surfaces from attachment of pathogens
IgA
Believed to be cell surface receptor of immunocompetent B cell
IgD
Main antibody of both primary and secondary responses
IgG
Binds to mast cells and basophils and triggers release of histamine
IgE
the most abundant antibody in blood plasma and is the only type that can cross the placental barrier
IgG
found mainly in secretions that bathe body surfaces, such as mucus and tears
IgA
the “troublemaker” antibodies involved in allergies
IgE
Only these can fix complement
IgM and IgG
the chief antibody ammunition used against cellular antigens, such as bacteria or mismatched red blood cells
Complement
antibody binding also “tags” antigen for phagocytosis
Opsonization
occurs when antibodies bind to specific sites on bacterial exotoxins or on viruses that can cause cell injury
Neutralization
clumping of foreign cells when the cross-linking involves cell-bound antigens
Agglutination
a reaction where the antigen-antibody complexes are so large that they become insoluble and settle out of solution
Precipitation
