Antigens and phagocytosis Flashcards
(16 cards)
What is on the surface of all cells?
chemical markers (for example, proteins) called antigens
Does each antigen have its own unique shape?
yes
What stimulates an immune response?
anything with different antigens to you
What happens in an immune response?
your body will recognise the antigen as foreign and will attack it
What is an antigen?
a protein found on the outside of cells that triggers an immune response
Antigens enable the immune system to identify what?
pathogens
cells from other organisms of the same species
abnormal body cells
toxins
Where are phagocytes made?
Bone marrow
Where do phagocytes travel?
in capillaries
What are the two types of phagocytes?
neutrophils and macrophages
What do neutrophils do?
engulf and digest pathogens (and dead human cells / debris)
What do macrophages do?
they can punch holes in the bacteria or stick proteins to the outside of the bacteria to make them more appealing for the neutrophils to destroy
What is phagocytosis?
cellular process of engulfing solid particles using the cell membrane - carried out by phagocytes
What is the first step of phagocytosis?
pathogen recognised as having foreign antigens. pathogen attaches to the phagocyte by surface receptors
What is the 2nd step of phagocytosis?
the pathogen is engulfed by the phagocyte by endocytosis forming a phagosome
What is the 3rd step of phagocytosis?
Lysosomes fuse to phagosome to form a phagolysosome and release H2O2, HCl and digestive enzymes into phagosome to digest pathogen
What is the final step of phagocytosis?
Harmless products removed by exocytosis or used by phagocyte
