Host defence in the lung Flashcards
what is our main defence in the lung against infection?
inflammation.
how does acute inflammation occur? [3 steps]
- vasodilation leads to exudation of plasma including antibodies.
- activation og biological cascades.
- migration of blood leukocytes into the tissues.
What is the specialist macrophage in the lung?
the alveolar macrophage.
What is the difference between chronic and acute inflammation?
any of these; Causative agent, Cells involved in response, onset, duration, outcomes.
why are macrophages described as a spectrum?
they can develop into many cells and can swap their phenotype.
What are the three main functions of the alveolar macrophage?
- Microbial killing
- co-ordination of the inflammatory response [cytokine production]
- induction and clearance of apoptotic cells.
What is meant by neutrophil apoptosis?
once the neutrophils have reached their target area and done their job they need to be removed to stop accumulation this is done via apoptosis [programmed cell death].
How do neutrophils migrate to a source of infection?
they can detect concentration gradients and move along it by moving its receptors to the leading edge.
how is the phagolysosome created?
by membrane invagination by the neutrophil and pinching phagosome fusion with granules.
What 3 steps allow a neutrophil to enter a cell?
- Margination with the help of selectins.
- adhesion to the membrane with the help of integrins.
- changes in structure of endothelium and in the neutrophil.
what is the role of respiratory epithelium?
to moisten and protect the airways. To protect and prevent pathogens from reaching the deep alveolar tissue, can be done by releasing mucus.
What types of molecules are included in the mucus that help to protect the lung?
water, carbs, proteins and lipids?
what molecules are secreted by the epithelium that play a role in host defence?
antiproteases, anti-fungal peptides, Surfactant.
What type of stratified epithelia is there in; 1.bronchus, 2. bronchioles, 3. alveolar.
- columnar
- cuboidal
- squamous
what is the much-cillary escalator?
the synchronised beating movement of the cilia which creates directional waves to move mucus up the airway.
What is a cough?
it is an expulsive reflex that protects the lung and respiratory passages from foreign bodies.
what is a sneeze?
a sneeze is the involuntary expulsion of air containing irritants from the nose.
why do infections usually occur at ciliated epithelia?
they have a larger surface area than all of the other airway epithelia.
how may a obstructive disease occur from through defence in the lung?
an abnormal response from airway epithelia to injury. e.g continuous large amounts of mucus released.
What is the difference between innate and adaptive immunity?
innate is non specific defence mechanisms that are immediate. Adaptive refers to antigen specific defence that isn’t necessarily immediate.
Describe how alveolar macrophages are ‘antigen presenting cells’
They ‘taste’ the environment, phagocytose foreign material and present the foreign antigen on their surface to stimulate other cells.
Why are lymphocytes and T cells called ‘effector cells’ ?
they recognise the antigen presenting macrophages and destroy them through immunoglobulins or T killer cells.
what is the basis of diversity In adaptive immunity?
It is the generation of pathogen-specific recognition regions in lymphocyte regions. [occurs via VDJ recombination]
What is meant by immune tolerance?
the state of unresponsiveness of the immune system, this can be to self or to pathogens?
