PHYSIOLOGY
PULMONARY PHYSIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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inspiration
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expiration
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Either A or B
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None of the above
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Detailed explanation-1: -The second phase is called expiration, or exhaling. When the lungs exhale, the diaphragm relaxes, and the volume of the thoracic cavity decreases, while the pressure within it increases. As a result, the lungs contract and air is forced out.
Detailed explanation-2: -Muscles that helpful in expanding the thoracic cavity are called the inspiratory muscles because they help in inhalation. Those that compress the thoracic cavity are called expiratory muscles and they induce exhalation.
Detailed explanation-3: -When drawing breath (i.e., during inspiration), the external intercostal muscles and diaphragm contract simultaneously. This causes the thorax to expand and inflate the lungs by creating negative pressure inside the thoracic cavity. During expiration, the contraction of these muscles ceases, causing them to relax.