Ch 43 Flashcards
pathogens
Agents that cause disease
-infect wide range of animals and humans
-subject to phagocytosis
immune systen
recognizes foreign bodies and respond w/ production of cells and proteins
innate immunity
-Defense active immediately upon infection
-present before any exposure to pathogens
-effective from birth
-non-specific responses to pathogens
-consists of external barriers, internal cellular, chemical, and barrier defenses
-rapid response
-phagocytosis, antimicrobial peptides
-found in all animals and plants
-foundation to adaptive immunity
-natural killer cells
-interferon
-protein and peptides attack pathogens or impede production
adaptive immunity
-acquired immunity
–develops after exposure
-very specific response to pathogens
-slower,delayed response
-2 types; humoral and cell-mediated immune response
-includes B and T cells
lysozyme
enzyme that breaks down bacterial wall
-in digetsive system w. chitin based barrier
phagocytosis
Ingestion and digestion of foreign substances including bacteria
-carried out by Hemocytes within hemolymph
defenses unique to vertebrates
-natural killer cells, interferons, and inflammatory response
phagocytic cells
-neutrophils: engulf and destroy pathogens
-macropahges: found throughout body/ “large eaters”m,o
-dendriticells: stimul.ate development of adaptive immunity
-eosinophils: discharge destructive enzymes
-recognize groups of pathogens by TLRs (toll-like receptors
natural killer cells
-circulate body and detect abnormal cells
-release chemical leading to cell death, inhibiting spread
interferon
-proteins provide innate defense by interfering w/ viruses and helping activate macrophages
completment system
-made up of 30 proteins
-cuases lysis of invading cells
-helps trigger inflammation
inflammatory response
-pain and swelling
-brought by molecules released during injury
-local or systemic
mast cells
type of connective tissue
-release histamine (triggers blood vessel to dilate and become more permeable)
cytokines
-released by macrophages and neutrophils
-signal molecules that enhance immune response
fever
-systemic inflammatory response
-triggered by pyrogens released by macrophages and toxins from pathogens
septic shock
-life threatening condition
-cause by overwhelming inflammatory response
lymphocytes
-what adaptive responses relies on
-type of leukocyte: white blood cells
2 types:
-mature in thymus (T cells) and bone marrow (B cells)
–each lymphocytes specialized to recognize specific type of molecule
T cells and B cells
-have receptor proteins that can bind to foreign molecules
-receptors for both are functionally diff.
-T cells find to antigen fragments (bound MHC molecules) displayed on host cell
-T cells: wipe out infected or cancerous cells and direct the immune response by helping B lymphocytes to eliminate invading pathogens
-B cells create antibodies
antigens
-substance that can elicit a response from B and T cells
antigen receptors
an antibody protein that is not secreted but is anchored to the B-cell membrane.
-B cell receptor: Y shaped, 2 identical heavy chain and light chains (constant region: vary little, variable regions: differ greatly, provide antigen specificity)
-T cell receptor: 2 diff. polypeptide chains ( called alpha and beta)
epitope
-small accessible part of antigen that binds to antigen receptor
antibody
-do not kill pathogen, just mark it
-neutralization and opsonization
-may bind to toxins in body fluids and prevent from exerting body cells
MHC molecules
(major histocompatibility complex)
- glycoproteins that display antigen fragment on cell surface
-diff. among genetically nonidentical individuals
-difference stimulate rejection of tissue grafts and organ transplants
-success increase if donor and recipient MHC tissue types are well matches
-immunosuppressive drugs facilitate transplantation
-lymphocytes in bone marrow transplants may cause donor tissue to reject transplantation
antigen presentation
-process where MHC molecules bind and transport antigen fragments to cell surface
-T cell can then bind to both antigen fragment and MHC (necessary for T cell to participate in adaptive immune response)
adaptive immunity 4 major characteristics
-diversity of lymphocytes and receptors
-self tolerance( lack of reactivity against an animals own molecules)
-B and T cells proliferate after activation
-Immunological memory
clonal selection
-proliferation (increase in #) of lymphocytes