Adachi T, Umezaki T, Matsuse T, Shin T
Department of Otolaryngology, Head and Neck Surgery, Saga Medical School, Nabeshima, Japan.
Otolaryngol Head Neck Surg. 1998 Apr;118(4):537-44. doi: 10.1177/019459989811800418.
The larynx has three functions: phonation, airway protection, and respiration. Few studies have dealt with laryngeal respiratory function. To elucidate respiratory regulation by the larynx, we studied the changes in the activity of the intrinsic laryngeal muscles during hypercapnia in decerebrated cats. The electromyographic activities of the posterior cricoarytenoid (PCA) and thyroarytenoid (TA) muscles were recorded simultaneously with an electromyogram of the diaphragm, endotracheal pressure, and concentrations of O2 and CO2. The activity of the intrinsic laryngeal muscles during hypercapnia (end-tidal CO2, 8% to 10%) was analyzed in comparison with that during eucapnia. In hypercapnia, both the PCA and TA muscles increased their activities, and the endotracheal pressure during expiration was elevated to a higher level than that in eucapnia. TA muscle activities returned to the level during eucapnia after ligation of the common carotid arteries. These findings suggest that hypercapnia causes a further widening of the glottis during inspiration to decrease inspiratory resistance and a further narrowing of the glottis during expiration to prevent alveolar collapse. Thus it may be concluded that the larynx actively participates in respiratory regulation under the control of the brain stem through a process of peripheral inputs from the carotid receptors.
发声、气道保护和呼吸。很少有研究涉及喉的呼吸功能。为了阐明喉对呼吸的调节作用，我们研究了去大脑猫在高碳酸血症期间喉内肌活动的变化。同时记录环杓后肌（PCA）和甲杓肌（TA）的肌电图活动以及膈肌肌电图、气管内压力、氧气和二氧化碳浓度。将高碳酸血症（呼气末二氧化碳浓度为8%至10%）期间喉内肌的活动与正常碳酸血症期间的活动进行比较分析。在高碳酸血症时，PCA和TA肌肉的活动均增加，呼气时的气管内压力升高至高于正常碳酸血症时的水平。结扎颈总动脉后，TA肌肉的活动恢复到正常碳酸血症时的水平。这些发现表明，高碳酸血症会导致吸气时声门进一步增宽以降低吸气阻力，呼气时声门进一步变窄以防止肺泡塌陷。因此，可以得出结论，喉在脑干的控制下通过来自颈动脉感受器的外周输入过程积极参与呼吸调节。
