Question

Which one of the following is the correct statement for respiration in humans?

• A. Cigarette smoking may lead to inflammation of bronchi
• B. Neural signals from pneumotoxic centre in pons region of brain can increase the duration of inspiration
• C. Workers in grinding and stone-breaking industries may suffer, from lung fibrosis
• D. About $90\%$ of carbon dioxide $(C{O}_2)$ is carried by haemoglobin as carbamino- haemoglobin

Answer 1

Answer: (C)

Cigarette smoking causes an immunogenic response. It results in increased levels of inflammatory markers. It may result in the development of irreversible narrowing of bronchial tubes due to inflammation and scarring. It causes cancer, chronic lung disease. The pneumotaxic centre in the pons region of the brainstem moderates the functions of the respiratory rhythm centre. It reduces the duration of inspiration and therefore alters the respiratory rate. Workers in grinding and stone-breaking industries may suffer from lung fibrosis. Exposure to environmental pollutants like silica, metal dust, bacteria and animal proteins can lead to lung fibrosis. Carbon dioxide is carried in the blood as bicarbonate, dissolved $C{O}_2$ and carbaminohemoglobin. About $29\%$ of it is carried as carbaminohaemoglobin.