the immune system Flashcards
types of immunity
innate or adaptive
what are the 3 lines of defence
- First line of defence are barriers (innate)
- Second line of defence protects from external invaders and internal rogues (innate)
- Third line of defence targets specific invaders and rogues (adaptive)
Function of innate immunity is to:
- Prevent and destroy entry of the pathogen into body
3.Eliminate cells that display MHC II - Activates adaptive (specific) immune response.
what lines of defence does innate immunity cover
first and second line of defense against infection and inflammation.
External barriers in the 1st line of defence
Anatomical Barriers
- skin
- mucous membranes
Chemical Barriers
acid, enzymes, sebum, etc
main components of the 2nd line of defence
- Cells
- Soluble proteins (Antimicrobial substances)
- Inflammatory mediators
cells of the 2nd LOD
Phagocytic cells (mast cells, neutrophils & macrophages)
Basophils & eosinophils
Natural killer cells (NK)
Dendritic cells
Soluble proteins (Antimicrobial substances)
Complement
Interferon
inflammatory mediators
Histamine, prostaglandins, kinins
mast cells
- Detects it then sends out chemicals eg; histamine, which triggers the inflammatory response
Neutrophils:
- Most abundant type of white blood cell. bodys first defence.
- Phagocytose the pathogen then die themselves (formation of pus)
- trigger inflammation
Macrophage:
detection, phagocytosis and destruction of bacteria and other harmful organisms.
* They DO NOT die after phagocytosing the pathogen (unlike neutrophils)
release inflammatory mediators
Basophils:
- Are associated exclusively with allergy response and hypersensitivity reactions
- produce histamine and serotonin that induce inflammation
Natural killer (NK) cells:
- ‘searching’ our body and scanning for infected/cancerous cells
destroy infected cells and cancer cells in your body.
induces apoptosis (self destruction)
Dendritic cells (DC)
- White blood cells made in bone marrow.
- Ingest pathogens but keep the antigen from them.
Inflammation functions to:
- Remove the infectious agent, such as microbes or toxins:
- Limit its effect on the body
- Repair or replace damaged tissue
- Alerts adaptive immunity
Humoral immunity
- Mediated by antibodies
Cell mediated immunity
- Mediated by T lymphocytes
