Respiratory system

1. Respiratory system Dr Kosar M. Ali

2. Introduction • The lungs ,with their combined alveolar surface area of 140 m², are directly open to the external environment. Thus structural, functional, or microbiological changes with in the lungs can be closely related to epidemiological,environmental,occupational and social status . • Primary respiratory diseases are responsible for a major burden for morbidity and ultimate deaths, in addition the lungs are often affected in multi system diseases. • Respiratory symptoms are common presenting symptoms to the family doctors .

3. Asthma affects 10% of adult population in the UK and bronchogenic cancer is one of the most killing cancer in the world. • The lung is major site for opportunistic infection especially in immune compromised patients.

4. Anatomy and physiology • The conducting airways, from nose to the alveoli connect the external environment with the extensive, thin , and vulnerable alveolar surface . • As air is inhaled through the upper airway it is filtered, heated to body temperature and fully saturated with water vapour . • Total airway cross section rises steeply from the narrowest point at the glottis to over 300cm²in the third generation respiratory bronchioles. • Air way patency is maintained by the cough reflex and by reinforcing cartilage rings. Normal breath sounds originate mainly from the rapid turbulent airflow in the larynx and theses central airways.

5. The multitude of small airways with in the lung parenchyma lack structural stiffness and are kept patent in health by radial traction from the network of elastin fibres in surrounding alveolar wall . Airflow is slow and normally silent in theses airways and gas transport occurs largely by diffusion in the final generation. • The acinus is the gas exchange unit of the lung and comprises, branching respiratory bronchioles and clusters of alveoli. Then filtered , moistened , and heated air makes a close contact with the pulmonary capillaries and o2 uptake and co2 exertion occurs.

6. The alveoli are lined with flattened epithelial cells ( type I pneumocytes) and a few more cuboidal ( type II pneumocytes), the latter produce surfactant a mixture of phospholipids, which reduce surface tension and counteract s the tendency of alveoli to collapse. • Type II pneumocytes can divide to type I after lung injury .

7. The major bronchial tree divide in to the Rt and Lt main bronchial tree ; the Rt lung has three lobes ( upper, middle, and lower lobes) and the Lt lung has two lobes ( upper and lower lobes), the lingular lobe on the left replaces Rt middle lobe. • The oblique fissure separate the upper lobe from the lower lobe on the left, while the transverse fissure separate the Rt upper lobe from the Rt middle lobe.

9. The bronchopulmonary segments, Rt side Upper lobe has 3 segments; anterior , posterior and apical Middle lobe has 2 segments; lateral and medial Lower lobe has 5 segments; apical , posterior basal , anterior basal, lateral basal, and medial basal. Lt side Upper lobe, divided in to proper upper lobe that has 3 segments ( anterior , posterior and apical) , and Lingular that has 2 segments ( superior and inferior). Lower lobe has 4 segments ; apical , posterior basal , anterior basal, and lateral basal.

12. Presenting symptoms of respiratory disease • Cough ; is the most frequent symptom of respiratory disease, it is caused by stimulation of the sensory nerves in the mucosa of the larynx, pharynx , trachea and bronchi. Common causes of cough includes; Post nasal drip Pharyngitis and laryngitis Croup Tracheitis Asthma Bronchitis ( acute or chronic) GERD

13. Ca bronchus Tuberculosis Pneumonia Bronchiectasis Pulmonary oedema Pulmonary fibrosis.

14. Dyspnoea Can be defined as the feeling of an uncomfortable need to breathe. It is unusual among sensation in having no defined receptors , and no localised representation in the brain. Dyspnoea can be divided in to acute and chronic. Causes of acute dyspnoea are; Acute pulmonary oedema Acute severe asthma Acute exacerbation of COPD Pneumothorax Pneumonia

15. pulmonary embolism Inhaled foreign body ARDS Laryngeal oedema Metabolic acidosis psychogenic

16. Causes of chronic dyspnoea IHD Chronic heart failure COPD Chronic asthma Pulmonary fibrosis Chronic PE Bronchial cancer Plural effusion Bronchial cancer Obesity Sever anaemia.

17. Chest pain Is a frequent manifestation of both cardiac and respiratory diseases, pleural or chest wall involvement by the lung disease gives rise to peripheral chest pain that increase by deep breath or coughing ( pleuretic chest pain) Causes of central chest pain MI Heart Valve lesions ( MVP, aortic dissection) Oesophagitis or spasm Massive PE Tracheitis Mediastinal mass Anxiety or emotional

18. Causes of peripheral chest pain Pneumonia TB Bronchial cancer Pneumothorax Osteoartheritis Costochondritis Rib fracture or injury Thorathic outlet syndrome

19. Haemoptysis Is coughing up blood , irrespective of it is amount is an alarming symptoms. Causes of haemoptysis; Bronchiectasis Foreign body Acute bronchitis Bronchial cancer Lung abscess TB Pneumonia

20. Trauma Pulmonary infarction Vasculitis (poly arteritisnodosa) Acute left ventricular failure Mitral stenosis Blood disorders ( haemophillia, leukaemia) Over medication with anti coagulants