secondary innate (non specific) immunity Flashcards
Facts about secondary defences
-they combat pathogens which have entered the body
-they are non specific meaning they’ll attack any pathogen
how are pathogens recognised as “foreign”
due to chemical markers called antigens on their cell surface membrane
describe the process which causes a fever?
-cytokines produced in primary defence stimulate hypothalamus to reset to a higher temperature
-specific immune responses work faster at a higher temperature
-higher temperature also inhibits pathogen reproduction
what is a type of antibody (protein) that attaches to the surface of a pathogen
opsonin
what is an oposonins role
to make it easier for phagocytic immune cells to bind to and engulf pathogens
where are neutrophils made
in the bone marrow
characteristics of neutrophils
-short lived
-produced in large numbers in an immediate response
features of neutrophils
-contains lysosomes containing lysin and multi-lobed nucleus
-well developed cytoskeleton
-many mitochondria and ribosomes
benefit of a multi-lobed nucleus
can squeeze through narrow gaps
what is the role of a well developed cytoskeleton
to help the cell change shape and engulf pathogens
stages of phagocytosis
-receptors on cell membrane of phagocyte recognise antibody molecules known as opsonins
-once engulfed by phagocyte, pathogen is contained in a phagosome
-lysosomes produce enzymes that digest the pathogen
what is the vesicle containing a pathogen called
phagosome
what are macrophages
large white blood cells
where are macrophages prodcued
in the bone marrow and mature in the lymph nodes
what do macrophages travel in the blood as
monocytes with a kidney bean shaped nuclei
what makes macrophages different
they engulf pathogens
-but then break them down and display the foreign antigens on their own cell surface membrane
what are macrophages recognised as
antigen presenting cells
what is the role of antigen presenting cells
can be recognised by other WBCs in the immune system and trigger a specific immune response
stages of phagocytosis in neutrophils
-neutrophil binds to opsonin attached to antigen of pathogen
-the pathogen is engulfed by endocytosis forming a phagosome
-lysosomes fuse to the phagosome and release lytic enzymes to it
-after digestion, harmless products can be absorbed into the cell
