Innate immunity Flashcards
lectures 1-4 p 1 - 29 (111 cards)
define aetiology
the causes of disease
define pathogenesis
how disease develops
necrosis
the death of a cells in an uncontrolled manner, often but not always due to hypoxia or ischaemia
apoptosis
genetically controlled programmed cell death.
- cell shrinks, nucleus compacts (pyknosis), nucleus fragments (karyorrhexis), and plasma membrane blebbing.
- the activation of proteases (caspases) commits the cell to mitochondrial or death receptor pathways.
- phagocytes engulf apoptotic bodies to prevent collateral damage to the surrounding tissues
commensals
the microorganisms always present in or on us but that only cause damage when epithelial barriers are breached.
what are pathogens
infectious organisms that cause disease
what are inflammatory diseases
disease caused by inappropriate or excessive immune responses
the afferent arm of the immune system
the mechanisms responsible for the discrimination of seld from non-self
the efferent limb of the immune system
the mechanisms triggered by the afferent arm that are responsible for inflammation and effector mechanisms to remove the pathogen and return the tissue to homeostasis.
innate immunity?
in place before infection and designed to react immediately
adaptive immunity
develops if the innate system fails to resolve the infection. highly specific for each pathogen
overlap between the innate and adaptive immune systems
- innate responses vary depending on the type of microorganism, and this directs the type of adaptive response that is generated.
2 - the adaptive systems co-operate with many of the effector mechanisms of the innate system to direct them in a highly specific manner.
3 components of the innate system
barriers, cells and soluble proteins
barriers of the innate system
skin, mucosal epithelia, anti-microbial chemicals
cells of the innate system
phagocytes such as neutrophils and macrophages, eosinophils, mast cels and natural killer cells
soluble proteins of the innate system
cytokines, acute phase proteins, complement, inflamatory mediators
bariers of the adaptive system
lymphocytes in the epithelia, antibodies at the mucosal surfaces
cells of the adaptive immune system
T and B lymphocytes
coluble proteins of the adaptive system
antibodies (immunoglobulins)
what does inflammation depend on
an intact vascular system, dead tissue wont undergo inflammation
what is inflammation
a stereotypic response to either microbial infection or tssue injury. the funtion is to eliminate the pathogen, repair the damage and return to a state of homeostasis.
- it is rapid and destructive but specific and self-limiting
trigger for inflammation
the activation of resident cells and complement with the release of inflammatory mediators
general events in inflammation
vasodilatation , increase vascular permeability, eigration of leucocytes, the accumilation of a cellular, protein rich exdate.
overview of the 5 steps of innate inflammatory immune responses
1 - recognition of infection or damage
2 - vascular response to injury
3 - elimintation of the pathogen
4 - resolution of the inflammation, repair and return to hoeostasis
5 - if the innate sytem fails to eliminate the pathogen then adaptive immunity is induced.