Final answer:
The paranasal sinuses are air-filled cavities in the skull that warm and humidify air, reduce skull weight, produce mucus, and enhance voice resonance. They are lined with nasal mucosa and when congested, can alter voice and cause discomfort.
Step-by-step explanation:
The paranasal sinuses are hollow, air-filled cavities located within bones of the skull such as the frontal, maxillary, sphenoidal, and ethmoidal bones. These cavities are an extension of the nasal cavity and contribute to a range of functions: they warm and humidify inhaled air, lighten the weight of the skull, produce mucus, and enhance voice resonance. When inflamed due to a cold or sinus infection, these sinuses can cause changes in voice quality and may lead to discomfort or pain.
The lining of the paranasal sinuses is made up of nasal mucosa, which plays a critical role in humidifying and warming the air that travels through the nasal passages. This adaptation is essential for protecting the respiratory tract from cold or dry air. Furthermore, as air resonates in these hollow spaces, it contributes to the tonal quality of our voice, which is why nasal congestion can change how we sound.