[amp_mcq option1=”The volume of the thorax decreases” option2=”The volume of the lungs decreases” option3=”The volume of the thorax increases” option4=”The lungs shrink” correct=”option1″]<\/p>\n
The correct answer is: A. The volume of the thorax decreases.<\/p>\n
When the diaphragm and external intercostal muscles contract, the volume of the thorax decreases. This causes the pressure in the lungs to decrease, which in turn causes the lungs to expand and fill with air.<\/p>\n
The diaphragm is a dome-shaped muscle that separates the chest cavity from the abdominal cavity. When the diaphragm contracts, it flattens out and increases the volume of the chest cavity. The external intercostal muscles are located between the ribs. When they contract, they lift the ribs up and out, which also increases the volume of the chest cavity.<\/p>\n
As the volume of the chest cavity increases, the pressure in the lungs decreases. This is because the pressure of the air in the lungs is always equal to the pressure of the air outside the lungs. When the pressure in the lungs decreases, the air outside the lungs pushes into the lungs, causing them to expand and fill with air.<\/p>\n
The opposite is also true. When the diaphragm and external intercostal muscles relax, the volume of the thorax decreases. This causes the pressure in the lungs to increase, which in turn causes the lungs to contract and empty of air.<\/p>\n","protected":false},"excerpt":{"rendered":"
[amp_mcq option1=”The volume of the thorax decreases” option2=”The volume of the lungs decreases” option3=”The volume of the thorax increases” option4=”The lungs shrink” correct=”option1″]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[15],"tags":[],"class_list":["post-54908","post","type-post","status-publish","format-standard","hentry","category-biology","no-featured-image-padding"],"yoast_head":"\n