Non-Specific Defences Against Diseases Flashcards
What is the Immune System?
A group of cells,tissues,organs and mechanisms that defend an organism against pathogens and other foreign substances.
What is an Immune Response?
Complex series of specific an non-specific processes involving a range off the cells and chemicals.
What will happen if the body successfully fights an infection?
It will respond more quickly and effectively if the same pathogen is re-encountered.
What are the physical barriers?
-Skin
-Skin Flora
-Mucous Membranes
-Lysozyme
How does the skin act as a physical barrier?
Acts as a barrier all around the body to prevent the entry of bacteria.
What does the skin produce?
Sebum, an oily substance that inhibits pathogen growth.
How does Skin Flora act as a Physical Barrier?
The skin has a naturally has a large population of natural health bacteria. These outcompete pathogens for surface space.
How does Mucous Membranes act as a Physical Barrier?
Gas exchange surfaces have a layer of mucus that trap pathogens.
What does this mucus contain?
The enzymes which destroy bacteria.
How do lysozyme’s work as a Physical Barrier?
In tears, urine and in stomach acid also destroys pathogens.
What happens if the skin is ruptured?
Pathogens may enter the blood.
How many stages in blood clotting?
3
What is the first stage in blood clotting?
Platelets rush to the site and they release 2 substances.
What 2 substances do they release?
Thromboplastin and Serotonin
What does serotonin cause?
Muscles to contract around reducing the gap
What is the second stage in blood clotting?
The clot dries out forming a hard scab keeping pathogen from entering.
What is the third stage in blood clotting?
Epidemical (skin) cells grow beneath the scab, collage fibres reinforce the skin cells.
What is inflammation?
The swelling of skin immediately around the rupture.
What is inflammation characterised by?
Pain, heat and redness
When are mast cells activated?
When skin is ruptured they release histamines and cytokines.
What are histamines?
Make blood vessels dilate, causing localised heat and redness.