Answer
Answer
1. This is positive pressure breathing. The air is forced itno the rescued by the rescuer. The pressure of air coming from the latter mus overcome pressure resistance from the former in order for the air to enter the trachea and bronchi and bronchioles of the rescued.
2. Inflation of the lung pushes the visceral pleura towards the parietal pleura and increases the intra- pleural pressure
Work Step by Step
4. Inhalation occurs when external intercostal muscles contract, the internal intercostal muscles relax an the diahragm contracts ; these movements have the effect of increasing the thoracic cavity. This decreases the intrapleural pressure and because of the cohesive influence of surfactant they cause the lungs to expand to fill the extra space, Because nature abhors a vacuum, air rushes in as pressure in the airways and alveoli decreases. Expiration occurs as the lungs and chest walls recoil and the external intercostals relax.
