3 Lines Of Defence Flashcards
(12 cards)
What are the three lines of defence?
- Physical and chemicals barriers
- Innate immune system
- Adaptive immune system
What does the 1st line of defence consist of?
Physical and chemical barriers like your skin, fluids such as tears and saliva, hair and mucous in the nose and throat, acid in the stomach, and diarrhoea
What happens in the 2nd line of defence
The infected area becomes inflamed, which is a response to the infection. Damaged cells release a chemical that causes an increase in blood flow to the affected area. White blood cells called neutrophils make their way over to consume bacteria
What happens in the 3rd line of defence
The lymphatic system is activated
What is the lymphatic system?
It is a series of vessel and capillaries that carry fluid from around your cells back to your heart. They contain lymph nodes.
What do lymph nodes do?
They contain a number of different WBC called lymphocytes and macrophages. They destroy the pathogens and help protect the body in the future. Macrophages consume bacteria and lymphocytes make antibodies, whcih makes the bacteria clump together so it is easier for the macrophage to eat.
True or false: pathogens have specific antibodies that act on it
True
What happens the first time lymphocytes meet a particular pathogen
They make antibodies against it. You are now immune to that pathogen because your body remember it
How does the body distinguish the difference between harmful pathogens and the body own cells
With antigens
What is an antigen
Antigens are surface markers on the cells.
Can the body recognise the difference between self or non-self(foreign) antigens
Yes
What is the cell that detects the presence of foreign antigens?
Lymphocytes. They are stimulated to produce antibodies
