Host defence in the lung Flashcards

1
Q

what is our main defence in the lung against infection?

A

inflammation.

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2
Q

how does acute inflammation occur? [3 steps]

A
  1. vasodilation leads to exudation of plasma including antibodies.
  2. activation og biological cascades.
  3. migration of blood leukocytes into the tissues.
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3
Q

What is the specialist macrophage in the lung?

A

the alveolar macrophage.

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4
Q

What is the difference between chronic and acute inflammation?

A

any of these; Causative agent, Cells involved in response, onset, duration, outcomes.

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5
Q

why are macrophages described as a spectrum?

A

they can develop into many cells and can swap their phenotype.

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6
Q

What are the three main functions of the alveolar macrophage?

A
  1. Microbial killing
  2. co-ordination of the inflammatory response [cytokine production]
  3. induction and clearance of apoptotic cells.
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7
Q

What is meant by neutrophil apoptosis?

A

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].

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8
Q

How do neutrophils migrate to a source of infection?

A

they can detect concentration gradients and move along it by moving its receptors to the leading edge.

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9
Q

how is the phagolysosome created?

A

by membrane invagination by the neutrophil and pinching phagosome fusion with granules.

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10
Q

What 3 steps allow a neutrophil to enter a cell?

A
  1. Margination with the help of selectins.
  2. adhesion to the membrane with the help of integrins.
  3. changes in structure of endothelium and in the neutrophil.
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11
Q

what is the role of respiratory epithelium?

A

to moisten and protect the airways. To protect and prevent pathogens from reaching the deep alveolar tissue, can be done by releasing mucus.

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12
Q

What types of molecules are included in the mucus that help to protect the lung?

A

water, carbs, proteins and lipids?

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13
Q

what molecules are secreted by the epithelium that play a role in host defence?

A

antiproteases, anti-fungal peptides, Surfactant.

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14
Q

What type of stratified epithelia is there in; 1.bronchus, 2. bronchioles, 3. alveolar.

A
  1. columnar
  2. cuboidal
  3. squamous
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15
Q

what is the much-cillary escalator?

A

the synchronised beating movement of the cilia which creates directional waves to move mucus up the airway.

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16
Q

What is a cough?

A

it is an expulsive reflex that protects the lung and respiratory passages from foreign bodies.

17
Q

what is a sneeze?

A

a sneeze is the involuntary expulsion of air containing irritants from the nose.

18
Q

why do infections usually occur at ciliated epithelia?

A

they have a larger surface area than all of the other airway epithelia.

19
Q

how may a obstructive disease occur from through defence in the lung?

A

an abnormal response from airway epithelia to injury. e.g continuous large amounts of mucus released.

20
Q

What is the difference between innate and adaptive immunity?

A

innate is non specific defence mechanisms that are immediate. Adaptive refers to antigen specific defence that isn’t necessarily immediate.

21
Q

Describe how alveolar macrophages are ‘antigen presenting cells’

A

They ‘taste’ the environment, phagocytose foreign material and present the foreign antigen on their surface to stimulate other cells.

22
Q

Why are lymphocytes and T cells called ‘effector cells’ ?

A

they recognise the antigen presenting macrophages and destroy them through immunoglobulins or T killer cells.

23
Q

what is the basis of diversity In adaptive immunity?

A

It is the generation of pathogen-specific recognition regions in lymphocyte regions. [occurs via VDJ recombination]

24
Q

What is meant by immune tolerance?

A

the state of unresponsiveness of the immune system, this can be to self or to pathogens?

25
Q

why is it essential to have tolerance?

A

without tolerance then an individual would be likely to develop an auto immune disease such as diabetes.

26
Q

What are the two main types of T cells?

A
  1. CD8 positive cytoxic cells - kill virally infected or cancer cells.
  2. CD4 positive T helper cells - produce cytokines to regulate other innate and adaptive defences.
27
Q

what are the characteristics of IgM?

A

It is produced early in immune response.

Opsonization, agglutination and complement activation.

28
Q

What are the characteristics of IgA?

A

It is found in tears, saliva and breast milk.
Resistant to proteases.
mucosal immunity [gut, lung]

29
Q

What are the characteristics of IgG?

A

> 80% of antibodies are IgG.
Cytotoxicity, neutralises toxins
opsonisation and complement activation.
placental transfer to foetus

30
Q

What are the characteristics of IgD?

A

Found on the surface of B cells.

Development of the immune response

31
Q

What are the characteristics of IgE?

A

they attach to mast cells.

they mediate allergic reactions.

32
Q

What do mast cells release?

A

Histamine.

PDG2, proteases, cytokines, IL’s

33
Q

what is a typical type 1 hypersensitivity reaction?

A

Anaphylaxis to food or drugs.

34
Q

what is the third type of hypersensitivity?

A

the creation of immune complexes and the activation of complementing molecules.

35
Q

List 5 environmental influences of lung disease.

A

Pollens, Infectious agents, Fungi, Pets, Animals, Air pollution.

36
Q

List 5 occupational influences on lung disease.

A

Flour, Car paint, Resins, Cleaning products, Wood dusts, Animal lab workers.

37
Q

What are the two forms of hypersensitivity pneumonitis?

A

Acute and Sub-Acute.

38
Q

What type of disease is hypersensitivity pneumonitis?

A

It is an immune complex disease; antigen reacts with antibody and creates an IgG response. Very specific environmental influences.

39
Q

What is COPD?

A

Chronic obstructive pulmonary disease, a long term progressive lung disease where lung capacity significantly decreases.