Читать книгу Understanding Anatomy and Physiology in Nursing - John Knight - Страница 150

The paranasal sinuses are air-filled cavities in the sphenoid, ethmoid, frontal and maxilla bones of the skull. These function primarily to reduce the weight of the skull and contribute to the conditioning of the inspired air. The sinuses also act as resonance chambers amplifying vocal sounds and giving each voice its own distinctive timbre; this role becomes very apparent when we suffer a head cold with sinus congestion which frequently imparts a tinny quality to the voice.

Infection and allergic responses cause the release of inflammatory mediators such as histamine, which initiates vasodilation of the capillaries underlying the epithelium of the nasal cavity. This can result in swelling and obstruction of the narrow openings to the paranasal sinuses, causing localised pain. In some cases, the sinuses may become chronically infected, leading to a painful condition called sinusitis. Histamine can also increase mucus production in the nasal cavity, leading to a streaming nose which is a common feature of many upper respiratory tract infections and allergies.