6.7 Response to infection Flashcards
Does not include humoral and cell mediated responses
What are physical barriers to infection
Skin - tough, consists of keratin
Stomach acid kills bacteria
Gut and skin flora
What are non specific responses of the body to infection
Inflammation
Fever
Lysozyme action
Phagocytosis
How does inflammation work?
Histamines released by white blood cells cause vasodilation which increases the flow of blood to the infected area and increases permeability of blood vessels
As a result, antibodies, white blood cells and plasma leak out into the infected tissue and destroy the pathogen
How does fever work?
The hypothalamus sets the body temperature higher
This decreases speed of pathogen reproduction and increases rate of specific immune response
Describe lysozome action
Lysozome is an enzyme found in secretions such as tears and mucus which kills bacterial cells by damaging their cell wall
Describe the process of phagocytosis
White blood cells engulf pathogens and destroy them by fusing a pathogen such as bacteria enclosed in a phagocytic vesicle with a lysosome
Where are B cells matured?
Bone marrow
Where are T cells matured?
Moved from the bone marrow to the thymus gland where they mature
What results in active immunity?
The production of antibodies by the immune system in response to the presence of an antigen
What results in passive immunity?
The introduction of antibodies from another person/animal
How is natural active immunity acquired?
Being exposed to an antigen/getting the disease
How is natural passive immunity acquired?
Crossing of mother’s antibodies through the placenta/breast milk
How is artificial active immunity acquired
Vaccinations which stimulate the immune system and lead to production of antibodies
How is artificial passive immunity acquired
Antibodies are injected
What is herd immunity?
Enough people have been vaccinated to make transmission of a disease very unlikely (80-90%)
