8. Innate Immune system Flashcards
The First and Second Line of Defence
Purpose of the first line of defence/ 3 types of barriers
‘prevention is better than a cure’
-physical (skin, hairs in nose)
- chemical ( stomach acid)
-microbiological (flora in vagina)
Physical
barriers block the pathogen from entering the body
intact skin, mucous secretions
Chemical
-lysozyme enzyme in tears and saliva which destroy bacterial cell walls
-antibacterial compounds in earwax
-stomach acid destroy pathogens eaten
- acidic sweat to prevent growth of pathogen
antibacterial proteins in semen
- low pH in vagina
Microbiological
presense of non-pathological bacteria (flora in the body) which prevent the growth of pathogenic bacteria by competing for resources
Second line of defence
if pathogens breach the first line, the second line kicks in (in minutes)
there are two different types cellular and non-cellular
cellular
leukocytes (white blood cells)
phagocytes (macrophages)
natural killer cells
non-cellular
interferons
inflammation
fever
Phagoctyes
the engulfing and digesting of foreign or dead material in the boy
phagoctyes contain enzymes which can break down engulfed material
some parts on pathogen can activate immune system
Natural killer cells
destroy infected or abnormal cells
they help by telling the cell to undergo apoptosis a form of programmed cell death
NKC are the most effective against viral infection
Interferon
chemical signal released from cell with virus
nearby cells become less susceptible by destroying DNA, cell destruction or activating immune response
Fever
abnormally high temperature
set of responses caused to raise temperature
increased body heat so the pathogens are not able to survive
Inflammation
increased blood flow to the infected area which increase the amount of immune cells and clear debris -> swelling, redness, pain, heat
