The chest is the area of origin for many of the body’s systems as it houses organs such as the heart, esophagus, trachea, lungs, and thoracic diaphragm.
The circulatory system does most of its work inside the chest. There, theheart平均每分钟节拍72次，每天循环高达2000加仑的血液。通过各种动脉和静脉网络，循环系统在整个身体中提供含氧血液和重要的营养素。
Just inside the chest, the heart circulates blood from around the body to thelungs,where the blood receives oxygen from capillaries.
Every breath you take pulls oxygen into your lungs to supply the body with oxygenated blood. As you exhale, you expel carbon dioxide, a waste gas produced by the body’s functioning.
Oxygen-rich blood then leaves the lungs and goes back to the heart. From there it is transported to major arteries such as the ascending and descending aortas. The aortas quickly deliver the blood to the chest and other parts of the body.
One important organ in the chest is thethymus, a small butterfly-shaped organ located between the heart and the sternum, or breastbone. This organ belongs to the immune system, and its job is to produce T cells, a type of white blood cell. These are formally known as T lymphocytes; the “T” stands for thymus, where the cells originate.
Basically, the T cell is the soldier the body sends to destroy invaders. The thymus not only creates the soldiers, but also “trains” those not quite ready for battle. When the thymus is finished with a cell, it is a multifunctional, adaptable invader-killing machine.
Also on defense inside the chest is theliver, the body’s largest glandular organ. It supports nearly every organ in the body in some facet. Among its functions are blood detoxification, fat breakdown, and old blood cell destruction.
The liver also creates bile, which helps thestomachdigest food through a cocktail of enzymes and acids.
Both the liver and the stomach are located in the lower chest region under thethoracic diaphragm, a sheet of muscle at the bottom of the rib cage that separates the chest cavity from the abdominal cavity.