Week 9 Flashcards
What are the 3 lines of defence?
1st
2nd
3rd
Briefly describe the first line of defence.
Non-specific so acts as a defence against any pathogen
Is the first line of defence specific?
No
What type of pathogens does the first line of defence act on?
All
Briefly describe the second line of defence.
Specific for bacteria and viruses.
Describe the specificity of the second line of defence
Specific to viruses and bacteria
What the of pathogens does the second line of defence act on?
Viruses and bacteria
Briefly describe the third line of defence
Specific for a particular pathogen
Describe the specificity of the third line of defence
Specific for a particular pathogen
What are innate defences against pathogens?
Mechanical barriers which prevent entry and help undergo phagocytosis.
If a pathogen manages to invade the body, what type of reaction occurs and why?
Inflammatory reaction to keep the infection contained.
What is the general purpose of an inflammatory reaction in the body?
To keep an infection localised and prevent its spread.
When is the first line of defence against pathogens present?
Constantly because it is innate (natural).
Is the first line of defence against pathogens physical or chemical?
Both
What is the first line of defence for the eyes and how does this work?
Lysozymes in the tears and other secretions dissolve pathogen cell walls.
How does the skin act as part of the first line of defence?
Acts as a physical barrier.
Produces antimicrobial fatty acids and is normal flora inhibits pathogen colonisation.
How does the stomach prevent pathogenic growth?
Has rapid changes in pH
How is colonisation of pathogens prevented in the urinary tract?
Flushing of the urinary tract.
How are pathogens expelled from the nose?
Removal of particles by rapid passage of air over cilia in the nasopharynx.
How are microorganisms prevented from entering the body via the trachea?
Microorganisms are suspended in the mucus and are moved out of the body by the cilia.
What prevents phagocytic colonisation in the lungs?
Mucus and phagocytes.
In the intestines, what prevents bacterial growth?
The normal bacterial flora.
What is the overall purpose of the second line of defence against pathogens?
Used to localise infection, neutralise toxins and repair tissue damage.