brjóstholið

Brjóstholið is the thoracic cavity, a space within the chest of vertebrates. It is enclosed by the ribs, sternum, and the thoracic portion of the vertebral column. The diaphragm, a muscular sheet, forms the floor of the thoracic cavity, separating it from the abdominal cavity. This cavity is crucial for respiration and protects vital organs.

The thoracic cavity contains the lungs, heart, esophagus, trachea, and major blood vessels such as the aorta and vena cava. The lungs, responsible for gas exchange, are housed within the pleural cavities, each surrounded by a double-layered membrane called the pleura. The heart, located in the mediastinum, a central compartment within the thoracic cavity, pumps blood throughout the body.

The structure of the thoracic cavity allows for the mechanics of breathing. When the diaphragm contracts and moves downward, and the intercostal muscles contract to lift the rib cage, the volume of the thoracic cavity increases, causing air to be drawn into the lungs. Conversely, relaxation of these muscles decreases the volume, forcing air out. This coordinated movement is essential for life. The rib cage also provides protection to the delicate organs within, safeguarding them from physical trauma.