Resipratory introduction Flashcards
Describe the process of gas exchange in the lungs
Gas exchange occurs in the alveoli, where oxygen diffuses from the alveolar air into the capillary blood, and carbon dioxide diffuses from the blood into the alveoli to be exhaled.
What is the significance of the alveolar-capillary membrane in gas exchange?
The alveolar-capillary membrane is a thin barrier that allows for efficient gas exchange between alveolar air and capillary blood, facilitating the diffusion of oxygen and carbon dioxide.
What are two classifications of respiratory disease? give two examples each.
- Obstructive
* Asthma
* COPD - Restrictive
* Interstitial lung disease
* cervical spine injury
What is Asthma?
A chronic respiratory condition characterised by intermittent reversible obstruction associated with inflammation and hyper-responsivness of the lungs
What are some common symptoms of Asthma?
- cough
- wheeze
- chest tightness
- shortness of breath
- variable expiratory flow limitation
What are some common triggers of asthma?
Aeitology
- Excersise
- Allergens
- irritant exposure
- changes in weather
- viral respiratory infections
- NSAIDS, Beta-Blockers,
How are NSAIDS contraindicated in Asthma?
- Inhibition of COX enzyme, decreased activity
- Decreased prostaglandin and Thromboxane A2 formation
- Results in the remaining precursors to be shunted into the leukoterine pathway
- Resulting in increased Leukoterine levels
- Resulting in increased Bronchoconstriction
How are Beta-Blockers contra-indicated in asthma?
- Bind to B2-receptors on bronchioles
- inhibit bronchodilation
- Resulting in increased bronchoconstriction
What is Bronchoconstriction?
The constriction of the airways in the lungs due to the tightening of surrounding smooth muscle,
Describe the Pathophysiology of asthma
- Trigger causes increased: eosiphonils, histamine, leukotrinenes
- Bronchiole wall oedema / increased mucus / bronchospasm results in bronchoconstriction
- Narrowing of the broncholes
- increased Resistance to CO2 therefore obstruction of outgoing airflow
- CO2 trapped in alveoli
- Results in dynamic hyperinflation of lungs
- difficulty breathing, short inhalation and prolonged expiration
How do allergens cause asthma exacerbation?
- Allergens activate dendritic cells
- Dendritic cells stimulate TH2 cells
- TH2 cells release IL-4, IL-5
- This leads to stimulation of eosinophils in bronchioles and also stimulates mast cells to release histamine and leukotrienes in bronchioles
- Results in Bronchospasm and Bronchial wall oedema
How can a viral URTI exacerbate asthma?
URIT = upper respiratory tract infenction
- Viruses activate dendritic cells
- Dendritic cells stimulate TH2 cells
- TH2 cells release IL-4, IL-5
- Causes stimulation of eosinophils in bronchioles and stimulates mast cells to release histamine and leukotrienes in bronchioles
- resulting in bronchospasm and bronchial wall oedema
Epidemiology of Asthma
- Woman are almost twice as likely to die from an asthma attack than men
- Lower Socioeconomic status = increased risk of uncontrolled symptoms
- The most common childhood long term illness
Tests used in diagnosis of asthma
- FeNO ( fractional exhaled nitric oxide) Test
Lung function tests: - Spirometry
- Bronchodilator reversabitlity (BDR)
- Peak Expiraratory flow variability
Direct bronchial challenge test with histamine or methacholine: - Direct bronchial challenge test with histamine or methacholine
Tests used in diagnosis of asthma - Lung function tests
Spirometry
Bronchodilator reversabitlity (BDR)
Peak Expiraratory flow variability
