Which membrane lines the sinuses?

The correct answer is the mucous membrane, which is an important lining for the sinuses. The sinuses, specifically the paranasal sinuses, are air-filled cavities located within the bones of the skull, and they communicate with the nasal cavities. The mucous membrane that lines these sinuses is crucial because it helps to moisten the air we breathe, traps particulate matter such as dust and pathogens, and contains cilia that help move mucus out of the sinuses and nasal passages.

Mucous membranes also play a role in immune defense, as they contain various cells that can help combat infections. This is particularly important in the sinuses, where blockages can lead to sinusitis if proper drainage and airflow are not maintained.

Other membrane types listed do not serve this function in the sinuses. For example, serous membranes are found lining body cavities that do not open to the outside, such as the pleura around the lungs or peritoneum in the abdomen. Synovial membranes are associated with joint cavities, producing synovial fluid to lubricate joints. Cutaneous membranes are the skin and are not involved in the lining of the sinuses. Thus, the role of the mucous membrane is essential for the proper functioning