Host Defence In Lungs Flashcards
What are the non immune barriers in the lungs?
Resp epithelium
Mucus
Coughing
How is resp epithelium a non immune barrier?
Acts as a barrier, contains anti pathogen proteins and mucus
How does mucus act as a non immune barrier?
Lubricant and protection
Mucocilliary escalator, cough up/swallowed mucus
How does coughing form a non immune barrier?
Inspiration, closing of epiglottis, increased thoracic pressure
Air forced out down p gradient
What is the main immune barrier in lungs?
The resident macrophage, ALVEOLAR MACROPHAGES
Alveolar macrophages are what % of all macrophages in the lung?
93%
How often do alveolar macrophages act?
What do they do?
Act on a regular basis
Phagocytose swiftly and destroy bacteria In alveoli swiftly with little help
Without inducing a massive immune response
What happens when the pathogen is too strong to deal with on its own?
Macrophages can illicit a huge response by recruiting neutrophil inflammatory response (6 steps)
Eg, in cases of pneumonia
How long do alveolar macrophages live for and arise from?
Long lived
Arise from monocytes (enter tissue and transform into macrophages- produced in bone marrow)
What is hypersensitivity?
Allergic hyper response, inflammation of self cells
Type 1 hypersensitivity
What is a response to?
What antibodies?
What Happens in response?
IgE
Allergies, acute anaphylaxis, asthma, hay fever
Binds to basophils, secrete histamine and prostaglandin
Bronchoconstriction + vasodilation, inflammatory response
Type 2 hypersensitivity Mediated by? Response to? Examples of it? What Happens?
IgM & IgG
Cytotoxic response
Eg, goodpastures, autoimmune disease
Tissue damage and altered receptors
Type 3 hypersensitivity
What happens?
IgG
Immune complex formation + deposition
Type 4 hypersensitivity
What happens
T cell mediated
Delayed response
