Obstructive Pulmonary Disorders (physiology) Flashcards
what are three obstructive airway diseases?
asthma, chronic bronchitis, emphysema
what are chronic bronchitis and emphysema known as ?
COPD
what is normal FEV1 volume?
3.5L-4L
What is normal FVC volume?
5L
what are spirometry values predicted upon?
age sex and height
how does peak expiratory flow work?
the first time a peak expiratory flow is done, a baseline is established. Consecutive readings are then compared to the baseline:
80-100% baseline= normal
<50%= airway obstruction
What does a peak expiratory flow allow a patient to do?
allows patient to measure respiratory rate at home
what is a normal peak expiratory flow range?
400-600litres/min
what is the clinical definition of chronic bronchitis?
cough productive of sputum most days for at least 3 consecutive months for 2 or more consecutive years
what may chronic bronchitis be confused with due to the similar presentation?
bronchial asthma - difficult to differentiate by history alone so investigations essential
when is ‘complicated’ chronic bronchitis?
- acute infective exacerbation i.e. bronchopneumonia
- FEV1 falls
what are the 4 main characteristics of chronic bronchitis?
- mucous hyper secretion (occludes lumen)
- fibrosis of BRONCHIOLAR WALLS
- airway oedema
- bronchoconstriction
what are the morphological changes in chronic bronchitis in large airways?
- increase in number and size (hyper plastic) of mucous glands and goblet cells
- inflammation and fibrosis is a minor component
what are the morphological changes in chronic bronchitis in small airways?
- goblet cells appear - normally none
- respiratory epithelium changes its character to produce more mucous (protective mechanism to chronic irritation)
what do all processes in chronic bronchitis lead to?
narrowing airway & hence airflow limitation
What is Emphysema?
Increase beyond normal in the size of airspaces distal to the terminal bronchiole arising from either dilatation or destruction of alveolar wall and without obvious fibrosis –> have hyper inflated lungs
what airway is the last one to have respiratory epithelium?
terminal bronchiole
what does the loss of alveolar walls in emphysema account for?
bigger spaces
where may this loss of alveolar wall occur within the acinus?
- Centriacinar
- Panacinar
- Periacinar
- Scar (irregular)
what is an acinus
terminal + respiratory bronchiole
alveolar duct
alveolar sac