Non Specific Immune Defenses Flashcards
(12 cards)
What is the immune system?
A set of organs tissues and cells that defend the body against pathogens, toxins produced by pathogens and cancer cells
What’s a pathogen?
A disease causing microorganism like bacteria, viruses and fungi
What is immunity?
The ability to resist infection by a pathogen
What are the physical defences in the body?
Closely packed epithelial cells are found in the skin and inner linings of the digesting and respiratory systems
These form a physical barrier to invading pathogens
What are the chemical defences/secretions?
Tears
Saliva
Mucus
Stomach acid
What causes the inflammatory response?
When the body suffers a physical injury like a cut or invading of microorganisms
Responds with localised defence mechanism(inflammatory response) at infected site
What is the inflammatory response?
The injury/infection occurs
Mast cells release histamine
Causes vasodilation and increased permeability of the capillaries
Injury becomes red and swollen
Increased blood flow(by vasodilation) leads to accumulation of phagocytes and clotting elements at the site of infection
What are phagocytes?
A type of white blood cell that recognise pathogens and destroy them by phagocytosis
What’s phagocytosis?
The process of engulfing and digesting foreign material
What happens during phagocytosis?
Engulfment- the cell membrane of the phagocyte surrounds the pathogen and takes it into the cell
Digestion- lysosomes are structures inside phagocytes that release digestive enzymes which destroy pathogens
What chemicals do phagocytes also release?
The release chemicals called cytokines which attract more phagocytes to the site of infection
What are cytokines?
Protein molecules that act as a signal to specific white blood cells causing them to accumulate at the site of infection
