Immunity Flashcards
What system is responsible for fighting infection?
Immune system
What type of cell helps fight off infection?
White blood cells (leukocytes)
What two types of white blood cell help fight infection?
Phagocytes
Lymphocytes
What is a phagocyte?
A type of white blood cell that performs phagocytosis
Define the term ‘phagocytosis’.
The process by which a cell engulfs a particle and digests it
What is step 1 of phagocytosis?
Chemotaxis may occur
Immune cells pick up chemical signals and migrate toward invading pathogens
Phagocytes are activated by inflammatory mediators
Define the term ‘chemotaxis’.
The movement of phagocytes toward a concentration of molecules
What is step 2 of phagocytosis?
Phagocyte attaches to the pathogen
What is step 3 of phagocytosis?
Phagocyte ingests the pathogen
Pathogen is enclosed in a vesicle called a phagosome
The phagosome transports the pathogen into the cell
What is step 4 of phagocytosis?
A lysosome fuses with the phagosome and the pathogen is digested
What is a lysosome?
A vesicle that contain hydrolytic enzymes that break down molecules
What is step 5 of phagocytosis?
Cellular waste is discharged from the cell by the process of exocytosis
Define the term ‘exocytosis’.
When cellular waste products travel in vesicles to the surface of the cell membrane and are released
What is a lymphocyte?
A type of white blood cell that fight infection and disease
How do lymphocytes protect the body against pathogens?
Recognise antigens
Detect antigens are foreign
Produce antibodies that cause pathogens to stick together making it easier for phagocytes to engulf them
Produce antitoxins to neutralise toxins produced by pathogens
Define the term ‘active immunity’.
When a specific type of lymphocyte called a memory lymphocyte can ‘remember’ the antigens from an infection by a previous pathogen
Antibodies will be produced much faster
Define the term ‘passive immunity’.
When an offspring receives antibodies from it’s mother
