Immune System Flashcards
Bacteria
prokaryote, unicellular organisms with DNA in the form of plasmids contained in cytoplasm, flagella, slime layer, cell membrane and wall
Virus
agents containing either RNA or DNA, with a protein coat. some have lipid envelopes
External Defences
Skin, mucus, hairs, cilia, acids
Protective reflexes
coughing, sneezing, vomiting and diarrhoea
Monocytes & Marcophages
monocytes differentiate into macrophages, which either look for pathogens or remain in a fixed place. particularly important in removing microbes and dying cells
Neutrophils
a granulated leucocyte, the first cells to move into the tissue to destroy the pathogen by phagocytosis
Dendritic cells
characterised by projections from cytoplasm, have the ability to detect, engulf and process foreign particles
Complement system
system of plasma proteins capable of being activated by pathogens or antibodies
Pyrogen
proteins that are capable of inducing a fever response, by being released during an inflammatory response, and stimulating the hypothalamus to reset the body’s internal thermostat
Histamine
chemical that causes vasodilation during the inflammatory response, and thus increases the permeability of the capillaries of the affected area
Heparin
chemical that prevents clotting. a clot of the fluid forms around the damaged area, which slows the spread of the pathogen into healthy tissues
Mast cells
type of granulocyte, capable of releasing various chemicals such as pyrogens and histamine and heparin
B-cells
lymphocytes that are produced and mature in the bone marrow, before becoming part of the lymphoid tissues
T-cells
lymphocytes that are produced in the bone marrow, mature in the thymus, before becoming part of the lymphoid tissues
Antigens
any substance capable of causing a specific immune response. they include virus particles, whole micro-organisms, parts of bacteria, toxins, molecules on cells
Antibodies
specialised proteins produced by plasma cells in response to a non-self antigen. belong to group of proteins called immunoglobulins
Antigen-presenting cells
specific cells that recognise non-self antigens and respond by: detecting the presence of a non-self antigen, engulfing the pathogen, digesting the pathogen, producing small fragments that move to the cell’s surface, and then presenting the antigen to lymphocytes
How antibodies work
- inactivating foreign enzymes or toxins by combining with them or inhibiting their reaction with other substances
- binding to the surface of viruses and preventing them from entering cells
- coating bacteria so that they are more easily consumed by phagocytes
- causing particles to clump together, i.e. agglutination
- dissolving organisms
- making soluble substances insoluble
