Chapter 3 Flashcards
What is the function of NADPH oxidase contained in secondary granules?
NADPH oxidase produces superoxide radicals that are converted into H2O2 (hydrogen peroxide) by superoxide dismutase
“NADPH oxidase produces superoxide radicals that are converted into hydrogen peroxide by superoxide dismutase”
What is the result of these reactions?
These reactions rapidly consume Hydrogen ions and have the direct effect of raising the pH of the phagosome.
This is useful because antimicrobial peptides and proteins (enzymes in the granules) are activated at a high pH and attack the trapped pathogen
What happens after the antimicrobial peptides and proteins attack the trapped pathogen in the phagosome?
the pH returns to neutral. Lysosomes fuse with the phagosome and allow complete breakdown of the pathogen.
Besides the rapid consumption of H+, what else do these reactions consume?
they transiently consume O2. This is called the “respiratory burst” which powers the neutrophil’s ferocious intracellular attack
What are the products of this respiratory burst? What do they do?
The products of this respiratory burst are toxic oxygen species. These toxic oxygen species breakdown bacterial cells
Besides the toxic oxygen species that are products of the respiratory burst, what other toxic species are involved?
toxic products can ALSO diffuse out of the neutrophil and damage neighboring cells
What limits the extent of damage done by hydrogen peroxide?
CATALSE degrades H2O2, limiting damage
Are superoxide radicals and H2O2 damaging to human cells?
YES - they both are
Is hydrogen produced or consumed in the respiratory burst?
CONSUMED – that’s how the pH rises
Which enzyme degrades H202
CATALSE — very efficient enzyme with a high turnover rate
During the respiratory burst, how many O2 molecules are produced and how many are consumed?
2 oxygen molecules are consumed and 1 is produced
What happens once granule contents are consumed?
the neutrophil dies
How many mechanisms of neutrophil death are there? name them
2:
Apoptosis (programmed cell death)
Netosis — neutrophil extracellular traps.
NET’s contain defensins, proteases, and calprotectin which trap microorganisms and kill them, even after the neutrophil itself is dead.
NET’s cause the neutrophil nucleus to swell and burst. The chromatin dissolves and is extruded from the cell
What is the effect of IL-1/IL-6/TNFa on the liver?
IL-1/IL-6/TNFa cause the liver to make ACUTE PHASE PROTEINS: C-reactive protein and mannose-binding lectin
C-reactive protein and mannose-binding lectin are part of….
an alternative way to activate complement and “ramp up” the response. Part of Lectin pathway
What are C-reactive protein and mannose-binding lectin also known as?
acute phase proteins
What effect does IL-1/IL-6/TNFa have on the bone marrow and endothelium?
IL-1/IL-6/TNFa cause the bone marrow to initiate Neutrophil mobilization in times of infection. Extra neutrophils are housed in the bone marrow/endothelium. When given the “word” from IL-1/IL-6/TNFa, they “dump” more neutrophils into the bloodstream
What is the ultimate effect of the liver producing acute phase proteins (C-reactive protein, mannose-binding lectin)
Activation of complement and opsonization
What is the ultimate effect of neutrophil mobilization by the bone marrow and endothelium?
greater phagocytosis
What effect does IL-1/IL-6/TNFa have on the hypothalamus?
Increased body temp (fever)
WHY does IL-1/IL-6/TNFa cause the hypothalamus to raise the body temperature and cause a fever?
because high temperatures favor eukaryotic cell division over prokaryotic. decreases viral/bacterial replication
What effect does IL-1/IL-6/TNFa have on fat and muscle?
IL-1/IL-6/TNFa cause fat and muscle (particularly near the site of infection) to increase protein synthesis and the hydrolysis of ATP which raises the temperature of the cells surrounding the infection. (keep in mind: inflammasome formation is affected) raise in temp also reduces bacterial/viral replication
Local inflammation can produce _____ effects by the actions of _____
local inflammation can produce SYSTEMIC effects by the actions of inflammatory cytokines
What is the common function between C-reactive protein, LPS, and mannose-binding lectin?
PATHOGEN RECOGNITION
