Immune System Flashcards
(25 cards)
Immunology
Study of body’s response to infectious agents, exogenous substances and abnormal cells
Categories of disease causing pathogens
Viruses, bacteria, fungi and parasites
Tasks of immune system
Distinguish between self and non-self proteins, pathogens and symbionts and healthy cells and diseased cells
Adaptive immunity
Vertebrates only, antibodies, develops by experience, slower, specific, enhanced with repeat exposure and has long-term memory component
Innate immunity
Uses macrophages, invertebrates and vertebrates, present from birth, non-specific, immediate, no enhancement with second exposure and no memory
Origin of leukocytes
Originate in bone marrow and hematopoetic cells, once mature they circulate in blood, lymphoid progenitors develop into adaptive immune cells and myeloid progenitors develop into innate immune cells
Cells of innate immune system
Monocytes and macrophages, dendritic cells and granulocytes
Macrophages
Engulf and kill invading microorganisms, dispose of pathogen infected cells targeted by adaptive immunity, induce inflammation by secretion of proteins that activate immune cells and are long lived
Monocytes
Differentiate into macrophages and dendritic cells in réponse to inflammation
Granulocytes
Neutrophils, eosinophils, basophils, mast cells and natural killer cells
Neutrophils
Densely packed granular cytoplasm, granules contain degradation enzymes, polymorphonuclear, short lived and large increase in numbers during immune response
Eosinophils
Less abundant than neutrophils, granules containing enzymes and toxic proteins that can be released and kill antibody-coated parasites
Basophils
Less abundant than neutrophils, granules containing enzymes and toxic proteins that can be released and promote responses of allergic reactions
Mast cells
Differentiate in tissues, allergic response as release granules containing histamine and involved in response to parasitic worms
Natural killer cells
Granular cytoplasm, recognise and kill abnormal cells by releasing lyric granules
Dendritic cells
Long, finger-like projections, take up microorganisms by phagocytosis, display pathogen antigens to T-lymphocytes and link innate and adaptive immunity
Response to infectious agent
Recognition by receptor which can be humoral or cell bound, communication by messengers or cascade systems and reaction mediated by effector cells that triggers immune cells and produces other molecules
Adaptive immune response cells
B cells and T cells
B cells
Antibody mediated immunity, T cell dependent, produced in bone marrow, each B cell has single antigen specificity, activated on binding to an antigen, activated B cells proliferate into plasma or memory cells
T cells
Mature in thymus and migrate to secondary lymphoid organs, cell mediated, 2 main types = T helper and T cytotoxic
Helper T cells
Help B cells produce antibodies, activate/enhance macrophage killing of pathogens and bind antigens presented by MHC class 2
T cytotoxic cells
Recognise and kill infected cells and bind antigens presented by MHC class 1
Immunological memory
Long term protection against disease, 1st exposure = primary immune response, 2nd exposure = secondary immune response which is faster and more efficient
Antigen presentation
Antigen exposed to T cells through antigen presentation, involves major histocompatilibility complex, distinguishes between self and non-self
