Low concentration of carbon dioxide: respiratory movement will be strengthened! Carbon dioxide will stimulate the respiratory center of the rabbit! Exciting the respiratory center! Thus strengthening the respiration! Increase the impact of dead space on respiratory movement. Due to the existence of dead space, every Not all the fresh air inhaled can reach the alveoli for gas exchange. The dead space increases, the alveolar ventilation volume is reduced, and the gas renewal rate is reduced. This leads to an increase in carbon dioxide in the blood, a decrease in oxygen partial pressure, a lengthening of the airways, and an increase in respiratory airway resistance. Larger, thereby deepening and accelerating breathing. After injecting lactic acid, the H content in the body is significantly increased, and H is an effective stimulator of peripheral receptors, so it can also reflexively cause breathing to strengthen. At the same time, H can also directly stimulate central chemoreceptors and Strengthen respiration, but H penetrates the blood-brain barrier slowly, so it mainly adjusts reflexively by stimulating peripheral chemoreceptors to deepen and speed up its respiration. Cutting off the vagus nerves on both sides of the rabbit lengthens and deepens the inhalation, and the breathing Deepening and slowing down. This is because the vagus nerve is mainly involved in the pulmonary stretch reflex of the lungs; it includes two parts: the lung expansion reflex and the lung collapse reflex. When the vagus nerves are cut off on both sides of the rabbit, it can be seen that the inhalation is prolonged and deepened, and the breathing is deepened and slowed down. This is because there are stretch receptors in the smooth muscles from the trachea to the bronchioles. When the lungs expand, the respiratory tract is stretched to expand, the receptors are excited, and the impulses are transmitted to the medulla oblongata through the vagus nerve. In the medulla oblongata, certain nerve connections are used to make the respiratory tract expand. The gas cutting mechanism is excited, cutting off inhalation and switching to exhalation, which accelerates the alternation of inhalation and exhalation and increases the breathing frequency. Therefore, the inhalation of rabbits whose vagus nerves are cut off on both sides becomes longer and deeper, and the breathing deepens and slows down. In addition, The vagus nerve is the afferent nerve of the peripheral chemoreceptor reflex. Cutting off the vagus nerves on both sides prevents the respiratory center from sensing peripheral chemical stimulation, thereby losing the peripheral chemoreceptor reflex regulation effect. Stimulating the central end of the vagus nerve causes more respiratory problems than when the vagus nerve is cut. The amplitude of the movement becomes larger and the frequency becomes slower. This is because the vagus nerve is an afferent nerve. When it is stimulated, more impulses will reach the medulla oblongata along the afferent fibers of the vagus nerve, and pass through certain neural connections in the medulla oblongata. Make the inhalation cut-off mechanism more exciting, extend the time to cut off inhalation and incoming breathing, make the breathing depth deeper and the frequency smaller; Answers found