secondary defence Flashcards
what is an antigen
a protein or glycoprotein intrinsic to the plasma membrane which are specific to the organism
what is an opsonin
a protein which attaches to the antigen on the pathogen surface
what is the role of an opsonin
enhance the ability of phagocytic cells to bind and engulf pathogens
what does it mean if an opsonin isnt specific
it can bind to multiple pathogens
are neutrophils short lived or long lived
short lived
describe phagocytosis
neutrophil binds to opsonin attached to the antigen of the pathogen
pathogen engulfed by endocytosis forming phagosome
Lysosomes fuse making phagolysosome releasing lytic enzymes
digest pathogen, harmless products absorbed
what is a phagosome
a vesicle containing a particle engulfed by a phagocyte
what organelle fuses with a phagosome
Lysosomes
describe the structure of a neutrophil
flexible nuclear membrane which causes a multi lobed nucleus
large number of lysosomes
flexible to squeeze through cell junctions
how are phagocytes adapted to their function
receptors on the plasma membrane to bind to opsonin
lobed nucleus to squeeze in narrow gaps
well developed cytoskeleton allows changing shape to engulf pathogens
many ribosomes to synthesis enzymes
How are macrophages different to neutrophils
They carry out phagocytosis but they do not destroy pathogens completely like neutrophils; instead they can display the antigens of the pathogens on their surface
They become antigen-presenting cell and can be recognised by lymphocytes
what cells become antigen presenting cells
Macrophages
where are macrophages and neutrophils manufactured
Bone marrow
what is the role of the antigen presenting cell
to enhance the chances of lymphocytes coming into contact with the foreign antigen by travelling around the cell.
what cell do macrophages travel in the blood as
Macrophages travel in the blood as monocytes.
then when they have left the blood they turn into macrophages
