5.1 - Defence Mechanisms Flashcards
The different types of pathogen The difference between non-specific and specific defence mechanisms The physical and chemical barriers to pathogens What antigens are (19 cards)
What are communicable diseases?
Diseases passed from one organism to another
What are pathogens?
Microorganisms causing communicable diseases
What are the four types of pathogens?
- Bacteria
- Fungi
- Viruses
- Protoctists
How do bacteria cause disease?
Produce toxins that damage cells
How do viruses cause disease?
Use host cells to replicate and destroy cells
How do protoctists cause disease?
Take over cells and break them open
How do fungi cause disease?
Digest living cells and produce toxins
What are the two types of defense mechanisms?
Non-specific and specific defenses
What are non-specific defenses?
Defenses that act quickly and respond the same for all pathogens
What are specific defenses?
Defenses that are slower and produce a specific response for each pathogen
What are non-specific barriers to prevent pathogen entry?
- Skin
- Mucous membranes
- Expulsive reflexes
- Blood clotting and wound repair
How does skin act as a barrier?
Physical barrier and produces sebum
How do mucous membranes act as a barrier?
Secrete mucus and use lysozymes
What are expulsive reflexes?
- Coughing and sneezing are methods for expelling foreign objects (or pathogens) from the gas exchange system.
- Vomiting and diarrhoea expel the contents of the gut along with any pathogens present.
How does blood clotting act as a barrier?
Seals wounds and forms a scab
How does inflammation act as a barrier?
Increases blood flow and vessel permeability
What are antigens?
Unique molecules on cell surfaces
What is the function of antigens?
Distinguish between self and non-self cells
What cells and molecules can antigens identify?
Pathogens
