17. BREATHING AND EXCHANGE OF GASES
- Respiratory rhythm centre (Inspiratory & Expiratory centres): In medulla oblongata. It regulates respiratory rhythms.
- Pneumotaxic centre: In Pons. It moderates functions of respiratory rhythm centre. Impulse from this centre reduces the duration of inspiration and thereby alter respiratory rate.
- Chemosensitive area: Seen adjacent to the rhythm centre. Increase in the concentration of CO2 and H+ activates this centre, which in turn signals rhythm centre. Receptors in aortic arch & carotid artery also recognize changes in CO2 & H+ concentration and send signals to rhythm centre.
DISORDERS OF RESPIRATORY SYSTEM
- Asthma: Difficulty in breathing causing wheezing due to inflammation of bronchi and bronchioles.
- Emphysema: Damage of alveolar walls. It decreases respiratory surface. Major cause is cigarette smoking.
- Occupational respiratory disorders: Certain industries produce so much dust. So, the defense mechanism of the body cannot cope with the situation. Long exposure causes inflammation leading to fibrosis (proliferation of fibrous tissues). It results in lung damage. Workers in such industries should wear protective masks.
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