DR Medhat MRCP

Respiratory Physiology
• Main components of respiration are ventilation, perfusion & diffusion:
1)
Ventilation (inspiration & expiration)
- Transport of O2 from external environment to alveoli (inspiration) &
transport of CO2 from alveoli to external environment (expiration).
- Factors affecting ventilation :
a) Air way patency (from nose & mouth till alveoli).
b) Respiratory muscles (didphragm & intercostal muscles).
c) Neurological control of ventilation
- Ventilation abnormalities :
a) Obstructive lung diseases COPD (chronic bronchitis/emphysema)
Asthma
Bronchiectasis
Bronchiolitis oblitrans
Cystic fibrosis
b) Restrictive lung diseases
Parenchymal (alveoli/interstitium)
Chest wall disease : e.g kyphoscoliosis.
ILD (fibrosis , sarcoidosis)
ARDS
Neuromuscular disease : GPS ,MG, Diaphragmatic paralysis)
Obesity hypoventilation syndrome (OHS)
2)
Perfusion :
- i.e blood supply reaching
the alveoli through pulmonary
arteries ,arterioles & capillaries.