the immune system Flashcards
(105 cards)
what is immunology?
the study of the immune system
what is the immune system?
an integrated system of cells and molecules that defends against disease and reacts against infectious pathogens
how can the immune system be manipulated and how can it malfunction?
it can be manipulated to protect us against diseases using vaccines
it can malfunction leading to immunodeficiencies, allergies, autoimmune diseases and graft rejection
what are immunodeficiencies?
susceptibility to infections because the immune system is impaired
what are allergies?
an overreaction of the immune system
what are autoimmune diseases?
diseases caused by the immune system attacking its own cells
what is graft rejection?
when transplants are rejected because the immune system recognises the cells as non-self and attacks them
what are immunological techniques?
when antibodies are used in research, diagnostics and drugs
what are the 2 branches of the immune system?
the innate immune system that we are born with
the adaptive immune system that adapts over our lifetime to the pathogens we encounter
where are white blood cells derived and what are the 2 lineages?
derived from pluripotent cells in adult bone marrow
gives rise to one lineage for myeloid cells (innate) and one for lymphoid cells (adaptive)
what is the innate immune system and what cells and molecules are involved?
it has broad specificity in recognising pathogens and isn’t improved by repeat infection because it doesn’t have a memory, it responds quickly
uses phagocytes and natural killer cells
contains soluble factors, lysozymes, the complement system and interferon proteins
what is the adaptive immune system and what cells and molecules are involved?
it is very specific in recognising pathogens, improves with repeat infections because it has memory but is slower
it uses B and T lymphocytes and antibody proteins
how does the skin protect against infections?
it secretes sebum containing fatty acids, lactic acid and lysozymes which help destroy pathogens
how do mucous tracts help protect against infections?
the epithelial cells lining the tracts contain cilia that remove debris
they produce mucous that traps pathogens
how do stomach cells and bacteria protect against infections?
cells lining the stomach release hydrochloric acid lowering the pH to prevent growth of pathogens
the natural flora of bacteria protect against pathogens
what are phagocytes?
white blood cells present in blood that can enter tissues
they are short-lived but fast acting and they take up pathogens and use lysozymes to hydrolyse them
what are neutrophils?
the most common type of phagocyte
they have granules containing specialised lysozymes
what are the 2 types of mononuclear phagocytes and what do they do?
monocytes found in the blood and macrophages found in tissues
they live longer and help initiate adaptive immune responses
what are microbe-associated molecular patterns (MAMPs)?
molecules on the surface of microbes that are recognised by pathogen-recognition receptors
what are natural killer cells and what are they important for?
a type of lymphocyte that will only kill virally infected host cells
they recognise self and non-self cells and defend against cancer
what is the complement system and how do they destroy pathogens?
a group of 20 proteins found in the blood
when the body is infected they are activated and causes bacterial cell lysis of gram-negative bacteria
what are defensins and how do they destroy pathogens?
positively charged peptides made by neutrophils
they insert into bacterial membranes and disrupt them
what are interferons and how do they destroy pathogens?
proteins produced by virally-infected cells
they bind to receptors on the surface of infected cells activating antiviral genes
they also activate macrophages and NK cells
what are cytokines and how do they destroy pathogens?
small proteins secreted from white blood cells and T cells
they bind to cells and regulate the immune system to alert the body to an infection
they cause changes in gene expression or cause cells to move to the site of an infection