Secondary Non-specific Defences Flashcards
What are antigens?
The markers that show when a pathogen is present by using chemical markers on its outer membrane. They also mark organelles to show that they are not pathogens and don’t need to be engulfed
What are opsonins?
Proteins that bind to the antigen on a pathogen and allow phagocytes to bind. They are not specific. They can attach to multiple organelles. They are meant to enhance the ability of phagocytic cells to bind and engulf the pathogen
What are phagocytes?
Specialised cells in blood and tissue fluid engulf and digest the pathogens.
What are neutrophils?
White blood cell that engulfs foreign matter and traps it in a large vacuole which fuses with lysosomes to digest the foreign matter.
Neutrophil binds to the opsonin attached to the antigen of the pathogen
Pathogen is engulfed by endocytosis forming phagosome
Lysosomes fuse to the phagosome and release lytic enzymes into it
After digestion the harmless products can be absorbed into the cell
What are Macrophages?
Larger cells manufactured in bone marrow. Travel in blood as
Monocytes. Role in initiating the starting response to invading pathogens. Engulfs but doesn’t fully digest. Antigen from surface of pathogen is saved and moved to a special protein. The cell becomes antigen-present cell when it is saved. exposed to surface for recognisation.
What is active immunity?
Cell moves around body where it can come into contact with specific cells that can activate immune response. T lymphocytes and B lymphocytes. 1 of T/B in one recognition site for the antigen. = higher chance of antigen presenting cells coming into contact with antigen again.
what is a secondary defence?
defences that are activated when the pathogen has entered the body
what are antigens?
a chemical marker.
what are opsonins?
protein that attach to the antigen surface of a pathogen.
what is a phagocytes
the first line of secondary defence is phagocytosis. specialised cells in the blood and tissue fluid engulf the pathogens.
what are neutrophils?
white blood cell that engulfs foreign matter and traps it in a large vacuole which fuses with lysosomes to digest foriegn matter
what is a macrophages
larger cell manufactured in bone marrow. important in initiating the specific responses to invading pathogen. if it engulfs a pathogen, it doesn’t fully digest it. antigen on surface is saved and moved to a protein complex on the surface of the cell. the cell becomes an antigen-presenting cell. it exposes the antigen on the surface so other cells that are apart of the immune system recognise the antigen.
what are the two forms of active immunity?
antigen presentation
specific immune response
what is a antigen presentation?
moves around the body where it can come into contact with specific cells that can activate full immune response. T lymphocytes and B lymphocytes. there is only one T and B cell within one site of antigen. role of the cell is to increase the chances the antigens will come into contact with them
what is a specific immune response
T and B cells are activated to produce antibodies that combat a pathogen and memory cells to offer immunity
