The sinuses are also known as paranasal sinuses and paranasal sinuses. Multiple air-containing bony cavities around the nasal cavity. The physiological role of the sinuses is as follows: 1. Increase the mucosal area of the respiratory zone and promote the role of warming and humidifying the inhaled airflow The human sinus mucosa is a continuation of the mucosa of the respiratory zone of the nasal cavity, and the increased mucosal area promotes the regulation of temperature and humidity of the inhaled airflow. The pressure in the sinus cavity of the maxillary sinus changes with breathing, but slower than the phase of breathing 0, 2 s. When the nasal cavity is open, the pressure changes very little, only ± 4 mmH2O of pressure change during calm breathing, but during movement its change can be 17 ~ 20 mmH2O; usually the gas exchange in the sinus cavity is both slight and slow, in addition to the need to maintain the normal state of the sinus itself, for the temperature and humidity of the inhaled airflow is difficult to Play a regulatory role.
2, the resonance of sound sinus for a resonator, and the end of the string device similar to the hollow wooden box, the sound from the larynx can play a resonant role, so that it is pleasing to the ear. However, in patients with sinus lesions or sinus surgery does not cause sound changes. The resonance of some animals is not closely related to the size of the sinus cavity; for example, the sinus cavity of cats and lions is small, but the sound is loud; the sinuses of rabbits and giraffes are large, but the sound is low.
3, reduce the weight of the skull, increase the buoyancy of the head in the water skull because of the presence of sinus cavity, the weight is lighter than the solid bone; especially to reduce the weight of the front of the skull, thus reducing the tension of the neck muscle, not only to make the head movement flexible, and easy to maintain body balance. In addition, the existence of sinus airflow cavity increases the buoyancy of the head in the water, and it is easy to make the head float out of the water when swimming or in the water for some reason.
4, buffering the impact force to protect important organs sinus filled with airflow, can buffer the impact of external pressure, so that the brain and orbital tissue from shock. However, it is believed that there must be a large volume of cavity to obtain the effect of buffering pressure; and the maximum volume of the sinus is below 50ml, so the buffering effect can be limited.
5, thermal insulation role of the sinuses as an insulator, both to prevent heat dissipation, but also to isolate the adverse effects of heat on important tissues. Such as the maxillary sinus can prevent the loss of heat in the nasal cavity, other sinuses can prevent the orbital tissue and brain tissue in the skull from the influence of the temperature in the nose. Because most of the cranial brain tissues and the sinuses exist at a certain distance, so its heat insulation effect is very limited.
6, enhance defense function Recently, it was found that there is a large amount of NO in the mucosal epithelium of the sinuses of healthy people, NO has antibacterial and antiviral effects in the host nasal mucosa defense function, and may have the role of upregulating cilia function.