Respiratory system

Dr Kosar M. Ali

IntroductionThe 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 .

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.

Anatomy and physiologyThe 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.

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.

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 .

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.

The bronchopulmonary segments,Rt sideUpper lobe has 3 segments; anterior , posterior

and apicalMiddle lobe has 2 segments; lateral and medialLower lobe has 5 segments; apical , posterior basal

, anterior basal, lateral basal, and medial basal.Lt sideUpper 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.

Presenting symptoms of respiratory diseaseCough ; 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 dripPharyngitis and laryngitisCroupTracheitisAsthmaBronchitis ( acute or chronic)GERD

Ca bronchusTuberculosisPneumoniaBronchiectasisPulmonary oedemaPulmonary fibrosis.

DyspnoeaCan 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 oedemaAcute severe asthmaAcute exacerbation of COPDPneumothoraxPneumonia

pulmonary embolismInhaled foreign bodyARDSLaryngeal oedemaMetabolic acidosispsychogenic

Causes of chronic dyspnoeaIHDChronic heart failureCOPDChronic asthmaPulmonary fibrosisChronic PEBronchial cancerPlural effusionBronchial cancerObesitySever anaemia.

Chest painIs 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 painMIHeart Valve lesions ( MVP, aortic dissection)Oesophagitis or spasmMassive PETracheitisMediastinal mass Anxiety or emotional

Causes of peripheral chest painPneumoniaTBBronchial cancerPneumothoraxOsteo artheritisCostochondritisRib fracture or injuryThorathic outlet syndrome

HaemoptysisIs coughing up blood , irrespective of it is

amount is an alarming symptoms.Causes of haemoptysis;BronchiectasisForeign bodyAcute bronchitisBronchial cancerLung abscess TBPneumonia

TraumaPulmonary infarctionVasculitis (poly arteritis nodosa)Acute left ventricular failureMitral stenosisBlood disorders ( haemophillia, leukaemia)Over medication with anti coagulants