Smoking and the Lung Flashcards
What are two things that govern how quickly you are able to get air out in the first second
How dilated the air tubes are and the elastic recoil of the lungs
What is FEV1
How quickly you are able to get air out in the first second
What happens during inspiration
Take a breath in: move diaphragm down and chest wall out with external intercostals, increase volume in chest cavity, decrease the pressure resulting in negative intrapleural pressure and air goes from high pressure to low pressure (helical springs stretched)
What happens during expiration
(normally passive): reliant on elastic recoil of lungs
Why do you get diminished patency in chronic bronchitis
Air tubes are full of mucus leading to diminished patency (diameter) meaning you can’t get as much air out.
Why do you lose elastic recoil in emphysema
Elastin degraded so lungs lose elastic recoil (over stretched spring), easy to inflate lungs but then lose elastic recoil
What is COPD
Umbrella term for chronic bronchitis, emphysema and asthma
What are obstructive diseases
COPD, chronic bronchitis, emphysema and asthma
What does your ability to breathe or blow out air depend on
- The patency of your airtubes
2. The elasticity of your lungs/ chest wall (or helical springs)
Why do you have an increased risk of pneumonia and acute bronchitis if you smoke
Smoking inhibits alveolar macrophage function and mucociliary clearance
What does smoking cause increased risk of
Pneumonia and acute bronchitis lung cancer (and loads of other cancers), difficult asthma, inflammatory (interstitial) lung disease (DIP, RIBLD)
How can interstitial lung disease be treated
By stopping smoking
What does smoking during pregnancy do
Increases the risk of uterine retardation
What does smoking before an operation make
Wound healing more difficult
What does cigarette smoke cause
Tissue injury and activates the inflammatory cascade (responsible for pathological damage)
Describe the effect of cigarette smoke in chronic bronchitis
Damages cilia, directly damages airway epithelium, inhibits leukocyte removal of bacterial and other pathogens
Why do smokers develop an overnight cough
They don’t smoke overnight meaning that their cilia go into overdrive
What is COPD
Chronic obstructive pulmonary disease. Chronic means long standing, obstructive means blocking. In COPD the airways are narrowed
Describe the aetiology of COPD
Cigarette smoke is dose dependant. Only 30% of smokers develop COPD-dose relationship. Genetic factors-number of genes associated (α1 antitrypsin deficiency etc.), this can be a cause of emphysema if you have never smoked a single cigarette. Occupational (coal dust, silica, cadmium etc.)- controversial, probably increase risk of COPD in smokers. Biomass fuel emission- poorly ventilated kitchens in countries such as Bangladesh and Pakistan. Other factors- nutrition (low diet in vitamin C&E and antioxidants), low birth weight, maternal smoking.
What do people with chronic bronchitis have
A cough and sputum on most days
What is emphysema
Abnormal and permanent dilation of the airspace distal to the terminal bronchioles with destruction of their walls
COPD can be describes as multicomponent and includes
Inflammation, mucociliary dysfunction, tissue damage
Describe inflammatory in COPD
Inflammation (respiratory pathogens) such as Haemophilus influenzae and Pseudomonas aeruginosa, secrete lipooligosaccharide, an inflammatory stimulus leading to an increase in neutrophils, macrophages, eosinophils and T-lymphocytes in various parts of the lung).
Describe mucociliary dysfunction in COPD
Hypersecretion and inhibited ciliary activity
Describe tissue damage in COPD
Bacterial colonisation damages epithelial cells
What are the signs and symptoms characteristic of COPD
Decline in lung function and exaserbations
Describe the pathology of chronic bronchitis
Hypertrophy of submucosal glands, increased number of goblet cells, muco-ciliary dysfunction. All lead to mucous hypersecretion and retention
Describe the consequences of chronic bronchitis
Inability to clear mucous. Leads to mucous retention and airway blocking. Retained mucous is also more likely to become infected, this also leads to greater airway inflammation and bronchial wall thickening and ‘narrowed airtubes’
What happens in emphysema
Neutrophils result in release of metalloproteinases which degrade elastin resulting in lungs losing their elastic recoil
What does degradation of elastin in emphysema lead to
Hyperinflation or ballooning of alveloi, destruction of alveolar walls, destruction of alveolar capillary walls loss of lung elasticity
What are the symptoms of COPD
Progressive breathlessness and exercise intolerance. Cough with sputum. Wheeze. “Winter bronchitis” or “exacerbations”. Fatigue. Weight loss/ loss of appetite. Oedema
Describe the clinical features you would find on examination of someone with COPD
Hyperinflated chest- air trapping. Breathing quickly/ using accessory muscles. Cachexic- loss of muscle mass. Reduced breath sounds/ wheezing
What does FEV1 depend on
Patency of airtubes and elastic recoil of the lungs
What is FEV1 reduced in
COPD
What is FEV1 used in
Diagnosing COPD and grade the severity.
What is FVC
Forced vital capacity- the volume of air blown out at the end of a forced expiratory manoeuver
What is FVC reduced in
Restrictive disorders
Describe FEV1/FVC ratio
. FEV1/FVC ratio- normal is >0.7, obstructive 0.7, but both FEV1 and FVC need to be low in terms of percentage predicted
How do lungs with emphysema appear on x-ray
Hyperventilated meaning that you are able to see more anterior ribs
