ANIMAL PHYSIOLOGY
GAS EXCHANGE IN HUMANS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Air flows from the area of lower pressure in the alveoli to the area of higher pressure in the atmosphere
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Air flows from the area of higher pressure in the alveoli to the area of lower pressure in the atmosphere
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Detailed explanation-1: -As the diaphragm and intercostal muscles relax, the lungs and thoracic tissues recoil, and the volume of the lungs decreases. This causes the pressure within the lungs to increase above that of the atmosphere, causing air to leave the lungs.
Detailed explanation-2: -Contraction and relaxation of the diaphragm and intercostals muscles (found between the ribs) cause most of the pressure changes that result in inspiration and expiration. These muscle movements and subsequent pressure changes cause air to either rush in or be forced out of the lungs.
Detailed explanation-3: -Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. This contraction creates a vacuum, which pulls air into the lungs. Upon exhalation, the diaphragm relaxes and returns to its domelike shape, and air is forced out of the lungs.
Detailed explanation-4: -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-5: -During inhalation, the diaphragm flattens and the ribs move upwards and outwards due to contraction of the intercostal muscles. This increases the volume of the thoracic cavity and the pressure decreases. As the outside pressure is higher, air gushes into the lungs.