Pulmonary conditions - Pathology 1 Flashcards
what is an acinus (terminal respiratory unit)
- this is a functional unit, the part of the respiratory tract distal to terminal bronchioles
- where the gas exchange occurs
for normal gas exchange what should only be allowed to be there structurally
- flat epithelial cell that forms the lining of the alveoli sac
- basement membrane of that
- blood
describe the structure of the trachea
- c shaped cartilage rings
- mucous glands
Describe the structure of the bronchi
- discontinuous cartilage plates
- mucous glands
describe the structure of bronchioles
- No cartilage or mucous glands
- terminal bronchioles are less than 2mm in diameter
- respiratory bronchioles is where the gas exchange begins
describe the structure of alveolar ducts
- flat epithelium
- no glands or cilia
Describe the structure of the alveolar sacs
- no glands
- no cilia
What is the definition of pulmonary oedema
- accumulation of fluid in the paraenchyma and interstitial of the lung
What is the usual cause of pulmonary oedema
- haemodynamic - usually cardiogenic due to a problem in the heart
What does pulmonary oedema look like on autopsy
- heavy wet lungs
- alveolar pink granular fluid in the alveoli - may contain haemosiderin-laden macrophages
- resolution or brown induration if long standing
What is diffuse alveolar damage (ARDS; Shock lung)
- oedema caused by injury to alveolar capillary endothelium
- rapidly developing life-threatening respiratory insufficiency
What can cause diffuse alveolar damage (ARDS; Shock lung)
- shock
- trauma
- sepsis
- viral infection
- noxious gases
- radiation
What does diffuse alveolar damage (ARDS; Shock lung) look like on microscopy
- oedema fluid and fibrinous membranes lining the alveoli
- does not resolve but proceeds to severe scarring and lung parenchyma is often lost
Name two types of pulmonary emboli
- large saddle emboli
- smaller emboli
What are large saddle emboli
- immediately fatal
- lodge at the bifurcation of pulmonary trunk
What are smaller emboli
- these lodge peripherally and result in characteristic wedge shaped infarcts
How do the pulmonary arteries become occluded
- pulmonary arteries occlusion by circulating clots usually from the lower limb veins in bed-ridden
What can cause pulmonary hypertension
- COPD
- left heart valvular disease
- recurrent thromboembolism
What can pulmonary hypertension cause to happen to the heart
- this can cause right ventricular hypertrophy and failure = chronic cor pulmonale
describe what happens to the airway in obstructive pulmonary disease
- increased resistance to airflow at any level
- this is due to airway narrowing or loss of recoil
Describe what happens to total lung capacity and FEV1 in obstructive airway
- there is no decrease in lung capacity
- reduced FEV1
What happens to cause a restrictive lung disease
- reduced expansion of lung parenchyma
- caused by chest wall disorders or interstitial/infiltrative diseases
What happens to total lung capacity and FEV1 in restrictive pulmonary diseases
- Decreased total lung capacity
- reduced TLC with proportionate reduction in FEV1
define chronic obstructive airway disease
- a group of disease characterised by obstruction to airflow - this obstruction can be intermittent, reversible or irreversible and at any level of the respiratory tract
Name examples of COPDs
- chronic bronchitis
- emphysema
- bronchial asthma
- bronchiectasis
what two COPDs are always co existent
- chronic bronchitis and emphysema
What causes chronic bronchitis and emphysema
- almost always entirely due to smoking