Final answer:
Decreased submandibular compliance is similar to respiratory restrictive diseases where tissues become stiff or fibrotic, leading to less movement and bendability, causing airway collapse upon exhalation and trapping air in the lungs.
Step-by-step explanation:
Conditions that decrease submandibular compliance include situations where tissues become stiff or fibrotic, similar to examples seen in respiratory restrictive diseases such as respiratory distress syndrome and pulmonary fibrosis. In these diseases, the airways become less compliant and are characterized by stiffness, leading to a decreased ability to move and bend the lung tissue. This reduction in compliance results in air trapping within the lungs, as the airway collapses upon exhalation, due to more positive intrapleural pressure, significantly affecting the ability to exhale air efficiently. This effect on exhalation can be measured by a reduced Forced or Functional Vital Capacity (FVC), which is the volume of air that can be forcibly breathed out after taking the deepest breath possible. Such conditions in submandibular tissues could similarly lead to a reduced ability to secrete saliva efficiently through the submandibular ducts.