HUMAN PHYSIOLOGY
BREATHING AND RESPIRATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Because the air that is contained in the cavity has more space therefore pressure goes down
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It does not decrease it increases
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Because intercostal mucles and diaphram relax
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None of the above
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Detailed explanation-1: -This decrease of pressure in the thoracic cavity relative to the environment makes the cavity less than the atmosphere (Figure 2a). Because of this drop in pressure, air rushes into the respiratory passages. To increase the volume of the lungs, the chest wall expands.
Detailed explanation-2: -This increases the space in your chest cavity, and your lungs expand into it. The muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale. As your lungs expand, air is sucked in through your nose or mouth.
Detailed explanation-3: -When the air pressure within the alveolar spaces falls below atmospheric pressure, air enters the lungs (inspiration), provided the larynx is open; when the air pressure within the alveoli exceeds atmospheric pressure, air is blown from the lungs (expiration).
Detailed explanation-4: -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.