EMBRYOLOGY
RESPIRATORY SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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the volume of the thoracic cavity increases and the pressure decreases, causing air to rush into the lungs.
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the volume of the thoracic cavity decreases and the pressure increases causing air to rush out of the lungs.
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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: -When the volume of the thoracic cavity increases, the pressure inside the thoracic cavity will decrease (along with the pressure inside of the lungs). This will cause air to flow from the outside into the lungs. This process is called inspiration.
Detailed explanation-3: -Lung volume expands because the diaphragm contracts and the intercostals muscles contract, thus expanding the thoracic cavity. This increase in the volume of the thoracic cavity lowers pressure compared to the atmosphere, so air rushes into the lungs, thus increasing its volume.