Category Archives: Respiratory disease

Examination of the respiratory system

The nose The anterior part of the nose can be examined using a nasal speculum and light source. In allergic rhinitis the mucosa lining the nasal septum and inferior turbinate appears swollen and a dark red or plum colour. Nasal polyps can also be identified, as can a frequent site of nasal haemorrhage (Little’s area). The chest Radiology has become an essential part of examination of the chest. Diseases

Respiratory symptoms

Runny, blocked nose and sneezing Nasal symptoms are extremely common. The differentiation between the common cold or allergic rhinitis as a cause of ‘runny nose’ (rhinorrhoea), nasal blockage and attacks of sneezing is difficult. In allergic rhinitis, symptoms may be seasonal, following contact with grass pollen, or perennial, when the house-dust mite is the important allergen. Colds are frequent

Defence mechanisms of the respiratory tract

Pulmonary disease often results from a failure of the many defence mechanisms that usually protect the lung in a healthy individual. These can be divided into physical and physiological mechanisms and humoral and cellular mechanisms. Physical and physiological mechanisms  HUMIDIFICATION-prevents dehydration of the epithelium. PARTICLE REMOVAL-over 90% of particles greater than 10 J.Lm in diameter are remove

Ventilation and perfusion relationships

For efficient gas exchange it is important that there is a match between ventilation of the alveoli (VA) and their perfusion (Q). There is a wide variation in the VA/Q ratio throughout both normal and diseased lung. In the normal lung the extreme relationships between alveolar ventilation and perfusion are: • Ventilation but no perfusion (physiological dead space) • Perfusion but no ventilation (physiolog

Physiology of the respiratory system

The nose The major functions of nasal breathing are: • To heat and moisten the air • To remove particulate matter About 10 000 litres of particle-laden air are inhaled daily. Deposited particles are removed from the nasal mucosa within 15 min, compared with 60-120 days from the alveolus. The relatively low flow rates and turbulence of inspired air are ideal for particle deposition, and few particles greate

The pleura

The pleura is a layer of connective tissue covered by a simple squamous epithelium. The visceral pleura covers the surface of the lung, lines the interlobar fissures, and is continuous at the hilum with the parietal pleura, which lines the inside of the hemithorax. At the hilum the visceral pleura continues alongside the branching bronchial tree for some distance before reflecting back to join the parietal p

Respiratory disease

Structure of the respiratory system The nose The anterior one-third of the nasal cavity is divided into right and left halves by the nasal septum. The nasal vestibule leads to the internal ostium (a) which is the narrowest part of the nasal cavity. This causes a 50% increased resistance to airflow when breathing through the nose rather than through the mouth. The respiratory region (b) is divided by three fo