Mechanics of respiration

1. MECHANISM OF RESPIRATION

2. ANATOMY OF RESPIRATORY SYSTEM

3. STEPS OF RESPIRATION PULMONARY VENTILATION EXTERNAL RESPIRATION OR PULMONARY RESPIRATION TRANSPORT OF GASES IN BLOOD INTERNAL RESPIRATION OR TISSUE RESPIRATION

4. STEPS OF RESPIRATION

5. MECHANICS OF BREATHING 2 PROCESSES- Inspiration - Inlow of atmospheric air into lungs. Expiration -Outflow of air from lungs into atmosphere.

6. Important Pressures Atmospheric Pressure –Pressure exerted by the air surrounding the body i.e 0cm water pressure Intrapulmonary Pressure / intraalveolar pressure –pressure exerted by the air within the lungs Intrapleural Pressure / intrathoracic pressure -pressure within the pleural cavity exerted by pleural fluid. Transpulmonary Pressure/recoil pressure

7. MUSCLE OF INSPIRATION Muscle of normal tidal inspiration- Diaphragm External intercostal Accessory Muscle of inspiration- Sternocleidomastoid Scalene Serratus Anterior Pectoralis major and minor Laryngeal muscle

8. MUSCLE OF EXPIRATION Internal intercostal Abdominal muscles include- Abdominal Rectii Transversus Abdominis Internal oblique

9. MUSCLES OF RESPIRATION

10. BOYLE’S LAW Pressure of gas is inversely proportional to volume of thoracic cavity. Normal size Gas molecules strike wall and exert pressure.

11. If volume increases,less pressure is exerted If volume decreases,more pressure is exerted

12. COMPLIANCE Ease with which lungs can be stretched. Compliance of lung is determined by- Elastic forces of lung tissue. Alveolar surface tension.

13. COMPLIANCE Low compliance Supine position High standing diaphragm Pulmonary fibrosis Surgical intervention Hydrothorax Pneumothorax High compliance Emphysema Old age

14. SURFACE TENSION IN LUNGS Thin layer fluid lines alveoli. Surface tension due to attraction between water molecule. Surface tension=force for alveoli to collapse or resist expansion

15. SURFACE TENSION Increase tendency of alveoli to collapse. Increase work of breathing. Causes pulmonary oedema . Alveolar instability.

16. TO OVERCOME SURFACE TENSION Surfactant secreted from type II cells. Important components- Dipalmitoylphosphatidylcholine Surfactant apoproteins Calcium ions

17. WORK OF BREATHING INCREASE IN – Exercise Obstructive lung diseases Restrictive lung diseases

18. Thank You