Zusammenfassung der Ressource
4.1 - Non Specific Defences
- Physical and Chemical Defences
- Epithelial Cells
- Form a physical barrier to
prevent entry of pathogens
- Skin
- Produce secretions
against infection
- Mucus in
trachea
- Lysozyme in tears
- Acid in the stomach
- The immune system protects the body
against pathogens, some toxins and
cancer cells
- Inflammatory
Response
- Caused by release of
histamine by mast cells
- Causes vasodilation of
arterioles
- Increases blood flow
- Increased capillary permeability
- Increased blood flow and
secretion of cytokines
- An accumulation of
phagocytes
- Delivery of antimicrobial proteins
- Kill
bacteria
- Delivery of clotting elements
- Form a clot to prevent microbes entering the
bloodstream
- Phagocytes and Natural
Killer Cells
- Phagocytes
- Phagocytes and NK cells
secrete cytokines
- Stimulate the specific
immune response
- Phagocytes recognise surface antigen
molecules on pathogens
- Destroy the pathogen by
phagocytosis
- Natural Killer Cells
- NK cells cause virally
infected cells to destroy
themselves by apoptosis
- Cause the production of
self-destructive/digestive enzymes within
the virally infected cell