Which one of the following is the correct statement for respiration in humans?
Which one of the following is the correct statement for respiration in humans?
Cigarette smoking may lead to inflammation of bronchi
Neural signals from pneumotoxic centre in pons region of brain can increase the duration of inspiration
Workers in grinding and stone breaking industries may suffer, from lung fibrosis
About $90 \%$ of carbon dioxide $\left(\mathrm{CO}_2\right)$ is carried by haemoglobin as carbamino haemoglobin
Solution
Irritating gases, fumes, dusts, etc., present in the work place result in lung disorders. Pneumoconiosis is a condition of permanent deposition of particulate matter in the lungs. Tissue reaction to these irritating substances causes proliferation of fibrous connective tissue called fibrosis. It is common in flour mill workers, iron mill workers, coal miners, stone grinders, etc.
A strong pneumotoxic signal from pons varoli reduces the inspiration duration to only 0.5 second while weak signal may prolong the inspiration duration to five seconds.