L3 Flashcards
Inflammatory response
-Chemical signals from tissue resident cells attract more cells to site of injury
-Neutrophils enter blood from bone marrow
-Neutrophils cling to capillary wall
-Chemical signals from tissue resident cells dilate blood vessels and make capillaries “leakier”
-Neutrophils squeeze through leaky capillary wall, following chemical trail to injury site
What are the signs of inflammation?
Pain, heat, swelling, redness
Stage 1 Phagocytosis
Phagocyte adheres to pathogens or debris
Stage 2 phago
Phagocyte forms pseudopods that engulf particles, forming phagosome
Stage 3 phago
Lysosome fuses with phagocytic vesivle forming a phagolysosome
Stage 4 phago
Toxic compounds and lysosomal enzymes (hydrolase enzymes) destroy pathogens
Stage 5 phago
Sometimes exocytosis of vesicle removes indigestible residual material
What is in the lysosome?
-Low pH
-Toxic materials eg reactive oxygen and nitrogen intermediates (hydrogen peroxide and nitric oxide)
-Enzymes
What enzymes are in the lysosome
-Proteases (protein)
-Lipases (lipids)
-Nucleases (nucleic acids)
What are complement proteins?
C1-9 proteins which clear pathogens from blood and tissue
What are the 3 complement pathways that can trigger complement cascade
Classical (immune response), Alternative, Lectin
What is happening in Classical pathway?
Antibody bound to pathogen binds to complement
What is happening in alternative pathway?
Pathogen binds complement to surface/pathogen component.
What is happening in lectin pathway?
carbohydrate components of microbes bind to complement
What are the 3 outcomes of complement cascade?
Label (opsonisation), Destroy (lysis) and Recruit
What happens in label opsonisation outcome?
Labels pathogens with antibody or C3b (eat me) for phagocytes.
What happens during Recruit outcome?
C5a and C3a act as peptide mediators of inflammation and recruit/attract phagocytes (chemotaxis) through Mast cells degranulated
What happens during destroy outcome?
C9 forms Membrane Attack Complex (MAC) pokes holes in bacterial cells and kill them
Microbes with C3b labels are phagocytosed
