GENERAL ANATOMY
RESPIRATORY SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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ribs go down and out
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pressure is low causing air to rush in
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pressure is high causing air to rush in
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volume is low
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Detailed explanation-1: -When the lungs inhale, the diaphragm contracts and pulls downward. At the same time, the muscles between the ribs contract and pull upward. This increases the size of the thoracic cavity and decreases the pressure inside. As a result, air rushes in and fills the lungs.
Detailed explanation-2: -During inspiration, the diaphragm and external intercostal muscles contract, causing the rib cage to expand and move outward, and expanding the thoracic cavity and lung volume. This creates a lower pressure within the lung than that of the atmosphere, causing air to be drawn into the lungs.
Detailed explanation-3: -During inspiration, the diaphragm contracts and the thoracic cavity increases in volume. This decreases the intraalveolar pressure so that air flows into the lungs.
Detailed explanation-4: -At sea level, the atmospheric pressure (i.e. the pressure exerted by the gases in the Earth’s atmosphere) is about 760 mmHg. During inhalation, the volume of the lungs increases and the pressure inside the lungs decreases below that of atmospheric pressure.