Biology XI: 17 Breathing & Exchange of Gases(4 Respiratory Volumes

Respiratory Volumes and Capacities, Regulation of Respiration, and Disorders of Respiratory System Respiratory Volumes and Capacities Respiratory volume Description Amount Tidal Volume (TV) Volume of air inspired or expired during normal respiration 500 mL Inspiratory reserve volume (IRV) Additional volume of air a person can inspire by forceful inspiration 2500 − 3000 mL Expiratory Reserve Volume (ERV) Additional volume of air a person can expire by forceful expiration 1000 − 1100 mL Residual Volume (RV) Volume of air remaining in the lungs even after forceful expiration 1100 − 1200 mL Inspiratory Capacity (IC) Total volume of air a person can inspire after normal inspiration 3000 − 3500 mL Expiratory Capacity (EC) Total volume of air a person can expire after normal expiration 1500 − 1600 mL Functional Residual Capacity (FRC) Volume of air that remains in the lungs after normal expiration 2200 − 2300 mL Vital capacity (VC) Maximum amount of air a person can breathe in/out after a forceful expiration/inspiration This may include ERV, TV, and IRV. Total Lung Capacity Total volume of air accommodated in lungs at the end of forceful inspiration This may include RV, ERV, TV, and IRV. Regulation of Respiration Centre of Respiratory Regulation − Respiratory Rhythm centre Pneumotaxic CentreLocation −Pons region of brainFunction − Moderates the function of Respiratory Rhythm Centre Chemo Sensitive AreaLocation − Adjacent to Rhythm CentreFunction − Highly sensitive to CO2 and H+As CO2 and H+ increase, this area gets activated so as to provide signals to eliminate them. Aortic arch and carotid artery associated receptorsFunction - They also sense changes in CO2 and H+ concentration. Disorders of Respiratory System Asthma Bronchi and bronchioles get inflammated. Difficulty in breathing Wheezing Emphysema Chronic disorder Major cause − cigarette smoking Alveolar walls damage and respiratory surface decreases Occupational Respiratory Disorders Particular industries such as grinding and stone breaking get affected. Long exposure to dust leads to inflammation ultimately resulting in fibrosis. Serious lung damage is caused. Prevention − wearing protective masks during work