AP BIOLOGY

Detailed explanation-1: -From a functional point of view, there are three groups of respiratory muscles: the diaphragm, the rib cage muscles and the abdominal muscles. Each group acts on the chest wall and its compartments, i.e. the lung-apposed rib cage, the diaphragm-apposed rib cage and the abdomen.

Detailed explanation-2: -The diaphragm is attached to the base of the sternum, the lower parts of the rib cage, and the spine. As the diaphragm contracts, it increases the length and diameter of the chest cavity and thus expands the lungs. The intercostal muscles and neck muscles help move the rib cage and thus assist in breathing.

Detailed explanation-3: -Primary Muscles The primary inspiratory muscles are the diaphragm and external intercostals.

Detailed explanation-4: -The scalene–intercostal–oblique muscles: a functional unit The external intercostal muscles are involved in inhalation. The internal intercostal muscles are involved in exhalation.

Detailed explanation-5: -Along with the diaphragm, the intercostal muscles are one of the most important groups of respiratory muscles. These muscles are attached between the ribs and are important in manipulating the width of the rib cage. There are three layers of intercostal muscles.