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The major muscle is called the diaphragm. It separates the thoracic and abdominal cavities. When it contracts, it moves downward, thereby increasing the volume of the thoracic cavity. In addition, the external intercostal muscles (between your ribs) will contract, and by doing that pull your ribcage outward and also increase volume.
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∙ 13y ago
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∙ 7y agoScalenes (Elevate rib cage, assist in inhalation)
Sternocleidomastoid (Elevate Rib Cage, assist in inhalation)
Pectoralis minor (Elevate Rib Cage, assist in inhalation)
External Intercostals (Elevate rib cage, assist in inhalation)
Diaphragm (Prime mover of inhalation)
All increase the size of the thoracic cavity.
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∙ 13y agoType your answer here... external intercostalis
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∙ 13y agoRectus Abdominus
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∙ 10y agoDiaphragm.
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What muscle contracts to expand the chest cavity?
The Diaphragm
What is the movement when your muscles move your ribs to make the lungs bigger and smaller?
It is air that does it, as well as the rib muscles themselves. The diaphragm contracts, expanding the internal area of the thoracic (chest) cavity, causing a drop in pressure. Air is then drawn through the nose into the lungs, which expand, causing the ribs to move to accomodate this.
Which is the major muscle for breathing?
The Diaphragm.When the diaphragm contracts, it increases the size of the thoracic cavity (chest), which lowers the air pressure, causing outside air to flow in.The external intercoastals are also used in breathing. They are the muscles on your ribs, that pull on your rib cage and help to expand the chest cavity.
What happens to lungs when you inhale?
what happens when you inhale is that air goes into your lungs and your lungs get bigger ...Actually, your diaphragm moves to expand the volume of your thoracic cavity, which pulls a partial vacuum on your lungs, causing them to expand FIRST...and THEN the partial vacuum created by your expanded lungs causes air to move into them. When you breath out, it causes the reverse to occur.
How does the diaphragm affect the lungs?
The diaphragm (also called the thoracic diaphragm) is a layer of muscle extending across the bottom of the ribcage. The diaphragm separates the thoracic cavity from the abdominal cavity. A diaphragm in anatomy is generally used to describe flat structures, like the urogenital and pelvic diaphragm. However when someone speaks of "the diaphragm" they generally mean the thoracic one. With regards to respiration, the diaphragm is a crucial aspect of the process. During inhalation, the diaphragm contracts, allowing the thoracic cavity to grow (the external intercostal muscles also aid expansion) allowing the lungs to take in more air. This also decreases intra-thoracic pressure, meaning when the thoracic cavity grows it creates suction which draws air into the lungs. When the diaphragm relaxes, air is exhaled thus relaxing (opposite of contracting) the diaphragm. This entire process happens every time a breath is taken.
The thoracic cavity is surrounded by a stiff rib cage while the abdominal cavity has a softer muscular wall Why?
The thoracic cavity contains the heart and lungs, both of which are constantly expanding and contracting. The ribs in the thoracic cavity serve both as protection and support, allowing the lungs to expand and contract without running the risk of putting itself into a dangerous situation, including even external threats (or more likely itself). The abdominal contents, opposingly, are more muscular and less prone to damage, and do not need such excessive protection. Moreover, other areas such as the brain are encased in a cranial cavity of bone, and like the thoracic cavity, the organs enclosed are quite fragile. The abdominal cavity, also, contains the stomach, which may expand, which is impossible when a layer of bone is surrounding it, as is expelling it's wastes into the pelvic cavity.
When you breath which muscle is doing the main contraction to force air in and out?
The diaphragm, a muscle below the lungs, contracts to pull air into the lungs. In order to forcefully exhale, both the abdominal muscles and the internal intercostal muscles can be contracted to compress the lungs.
How does the diaphragm pull air into and out of the lungs?
When the diaphragm expands, causes the lungs to become smaller forcing all the air in the lungs to be pushed out since there is more pressure. When the diaphragm contracts, it makes more room for the lungs to expand, forcing air in the lungs since there is more space.
The thoracic cavity is surrounded by stiff rib cage while the abodominal cvity has a softer muscular wall?
I realize that this was meant to be a question, and one, if I may add, that is remarkable similar to one I recently answered, in which case I will paste my answer from the last one. The thoracic cavity contains the heart and lungs, both of which are constantly expanding and contracting. The ribs in the thoracic cavity serve both as protection and support, allowing the lungs to expand and contract without running the risk of putting itself into a dangerous situation, including even external threats (or more likely itself). The abdominal contents, opposingly, are more muscular and less prone to damage, and do not need such excessive protection. Moreover, other areas such as the brain are encased in a cranial cavity of bone, and like the thoracic cavity, the organs enclosed are quite fragile. The abdominal cavity, also, contains the stomach, which may expand, which is impossible when a layer of bone is surrounding it, as is expelling it's wastes into the pelvic cavity.
Why do you think the rib cage is not solid sheet like the skull?
If the ribcage were a solid sheet like the skull, it would be difficult for the thoracic cavity to expand and contract with inspiration and expiration.
How do the lungs work with the rib cage?
The ribcage protects the lungs. They don't necessarily "work together".
How do pressure changes within the chest cavity cause inspiration and expiration?
The diaphragm contracts, causing the lungs to expand. This creates a 'pressure difference' and air fills the lungs. When the diaphragm relaxes, it 'squeezes'[ the lungs, forcing the unabsorbed air (and waste gasses) back out again.
