Innate Immune System Flashcards
What are the three lines of immune defence?
- First line - surface membrane barriers
- Second line - innate immune cells and molecules
- Third line - adaptive immunity
What is the role of commensal bacteria in innate immunity?
They compete with pathogens for resources helping prevent colonisation
What are the four main functions of the innate immune system?
- Immediate
- Non specific defence using barriers
- Secretions
- Innate immune cells
What are three examples of professional phagocytic cells?
- Neutrophils
- Macrophages
- Dendritic cells
What is chemotaxis in phagocytosis?
Movement of phagocytes toward a chemical signal
What are the five steps of phagocytosis?
- Chemotaxis
- Adherence
- Ingestion
- Digestion
- Waste release
What increases the efficiency of phagocytosis?
Opsonisation by complement proteins and antibodies
What is the function of the membrane attack complex?
Forms pores in bacterial membranes leading to cell lysis
What are the five signs of inflammation?
- Redness
- Heat
- Swelling
- Pain
- Loss of function
What are the five key phases of inflammation?
- Vascular changes
- Chemotaxis
- Cellular infiltration
- Fever
- Healing
What is margination in inflammation?
Leukocytes moving to the vessel walls in response to inflammation
What are selectins and integrins?
Adhesion molecules that mediate leukocyte rolling and adhesion to endothelium
What is extravasation?
Movement of leukocytes out of blood vessels toward tissue injury
What are natural killer cells?
Large granular lymphocytes that kill tumor and virus infected cells without antigen specificity
What cytotoxic substances do NK cells use?
Granzymes and perforin which forms pores in target cells
Which immune cells participate in both phagocytosis and antigen presentation?
Dendritic cells and macrophages
What role does histamine play in inflammation?
It increases vascular permeability and vasodilation promoting leukocyte infiltration
Which immune cells release histamines?
Mast cells and basophils
