Topic 2- Phagocytosis Flashcards
What are phagocytes?
White blood cells
Where are phogocytes continuously produced?
In the bone marrow
What are the two types of phagocytes
-neutrophils
-macrophage
What is the role of phagocytes?
to recognise and engulf pathogens- this is known as phogocytosis
What is phagocytosis an example of?
Non-specific immune response
Explain the 1st step of phagocytosis- chemotaxis
-Chemicals released by pathogens, as well as chemicals released by body cells under attack
attract phagocytes
What is the 2nd step of phagocytosis?
-Phagocytes move towards the site of infection, where pathogens can be identified due to the presence of pathogenic antigens
-Phagocytes have receptor proteins on their surface that recognise antigens as non-self
What is the 3rd step of phagocytosis?
The phagocyte attaches to the pathogen by binding to its antigens
Explain the 4th step of phagocytosis-endocytosis.
Once attached to a pathogen the cell surface membrane of the phagocyte extends out and around the pathogen, engulfing it and trapping the pathogen within a phagocytic vacuole
What is a phagosome?
The phagocytic vacuole formed around a pathogen once it has been engulfed by a neutrophil
(5th step) What is a phagolysome?
The phagocytic vacuole fuses with a lysosome
What is the 6th step?
The lysosome releases digestive enzymes called lysozymes to digest the pathogen
What is the 7th step?
The products of pathogen digestion can sometimes be displayed on the cell surface of the phagocyte (this occurs in macrophages) to trigger the specific immune response
