Final answer:
The rate of breathing is chiefly regulated by the level of carbon dioxide in the blood, which is detected by chemoreceptors that signal the brain's respiratory centers to adjust the respiratory rate and depth to maintain homeostasis.
Step-by-step explanation:
Factors Influencing Respiratory Rate
The rate of breathing is primarily dependent on chemical factors in the blood, particularly the level of carbon dioxide (CO2). The brain's respiratory centers are stimulated by a rise in carbon dioxide or a decline in oxygen levels in the blood. These changes are detected by chemoreceptors in the brain and in the peripheral vascular system, particularly in the aortic arch and carotid arteries.
The body's response to high carbon dioxide levels involves an increase in the respiratory rate and depth to expel the excess CO2 and balance the pH level of the blood. While oxygen levels are also important, it is the partial pressure of CO2 that is more tightly regulated to maintain homeostasis. This regulation is a fundamental aspect of the body's respiratory system to ensure that gas exchange occurs efficiently, allowing oxygen to be taken up by blood and carbon dioxide to be exhaled.
Furthermore, the medulla oblongata and pons in the brain regulate the respiratory rate in response to systemic stimuli through a negative-feedback mechanism. The peripheral chemoreceptors are sensitive to large changes in dissolved oxygen levels, and they stimulate increased respiratory activity when these levels fall below a certain threshold, generally around 60 mm Hg.