Lecture 14 - Pathogen host relationships Flashcards
what are the 9 ways in which microorganisms damage the host
- exotoxins
- endotoxins
- cell wall fragments
- hydrolytic enzymes
- inhibition of secretory products
- invasion and intracellular multiplication
- induction of autoantibodies
- mutation
- obstruction
what are the 5 common host responses?
- cytokines
- pyrexia (fever)
- leukocytosis (re-population)
- acute phase proteins (limit damage and resolve infection)
- endocrine changes (increase in glucocorticoid steroids)
what are the 4 main types of inflammation?
- suppuration (solid tissue, pyogenic organisms)
- abscess
- ulcers (epithelial lining)
- cellulitis
what are the cardinal signs of a local skin infection?
- redness
- swelling
- heat
- pain
- loss of function
what are the non-visible signs of a local infection?
- increased body temp
- swollen lymph glands
describe the steps taken by the IS against a local skin infection
- activation of local blood vessels
- heat and redness due to increased blood flow
- leakage of plasma into tissue (swelling)
- swelling is alleviated by fluid entering the lymph vessels
what mechanism happens during infection that results in acute inflammation?
local vasodilation due to control via pre-capillary sphincters
what is pus the result of?
neutrophil phagocytosis
what is pus made of?
- dead neutrophils
- dead bacteria
- dead body cells
- other proteins
during a local infection, what do neutrophils increase the action of?
they produce antigens, which are picked up by antigen presenting cells e.g dendritic cells, which then enter lymphatic vessels and go to secondary lymph organs (nodes)
what are the goals of the local tissue response in the innate immune system?
- prevent spread
- fast, raise the alarm
- minimise tissue damage
- provide antigens from the infection and deliver them to the lymph nodes
what are the secondary organs of the lymphatic system
- adenoids
- spleen
- 600 ish lymph nodes
describe the supply of the circulatory and lymphatic systems
plasma from blood into tissues (interstitial fluid) returns as lymph through lymphatic vessels, then goes through the lymph nodes and to the thoracic duct for return
what are the 4 ways antigens can get to the lymph nodes?
- as debris or a free antigen flowing in the lymph fluid
- delivered by phagocytes
- delivered by specialised APCs (dendritic cells)
- injected directly
- produced in the LN
describe lymphatic flow
afferent lymphatic vessel -> subcapsular sinus -> trabecular sinus -> medullary sinus -> efferent lymphatic vessel
where do B and T cells reside?
lymph nodes
- t cells reside in CD3+ cells
- B cells reside in C19/C20
