Summary
The medulla adjusts breathing rate in response to blood CO2 and pH detected by chemoreceptors.
In depth
Central chemoreceptors detect CO2-driven pH change in cerebrospinal fluid; peripheral chemoreceptors detect low O2. The medullary respiratory centre sets rhythm, with pons modulation. CO2 is the main driver, not oxygen.
Respiratory centres in medulla and pons generate rhythm. CO2 is the main drive; low oxygen is a backup. Voluntary control comes from the cortex.
Example: chronic lung disease patients may rely on hypoxic drive.
The respiratory centres in the medulla (dorsal and ventral groups with the pre-Botzinger complex generating rhythm) and pons (pneumotaxic and apneustic centres) set the pattern. CO2 is the main drive: a rise in arterial PCO2 by 1 mmHg increases ventilation sharply via pH changes at central chemoreceptors. Peripheral chemoreceptors in carotid and aortic bodies respond to low PO2 (below about 60 mmHg), high CO2 and low pH. Stretch receptors prevent overinflation (Hering-Breuer reflex).
Voluntary control from the cortex lets us hold breath, until CO2 builds up. In chronic lung disease with high CO2, the drive may shift to hypoxia, so too much oxygen can reduce breathing. Opioids suppress the centres, causing overdose deaths. Sleep apnoea involves repeated airway collapse.
Remember: we breathe mostly in response to rising CO2, not falling oxygen.
Frequently asked questions
What is Respiratory Control?
The medulla adjusts breathing rate in response to blood CO2 and pH detected by chemoreceptors.
Which area of biology covers Respiratory Control, and how advanced is it?
Respiratory Control is one of the 51 topics in Human Physiology. It is rated Advanced, so it suits learners who want specialist depth. Related topics in this area include Renal Autoregulation, Respiratory System, Altitude Physiology.
Can you give an example of Respiratory Control?
Holding your breath ends because CO2 rises.
What should I learn before Respiratory Control?
Work through the Beginner topics in Human Physiology first, such as Homeostasis, Tissues and Organs, Skeletal System, then return to Respiratory Control. Advanced topics assume the Intermediate vocabulary.
What topics are related to Respiratory Control?
The closest topics to Respiratory Control are Renal Autoregulation, Respiratory System, Altitude Physiology, Exercise Physiology. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Respiratory Control?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Respiratory Control. To practise the whole of Human Physiology, use the Human Physiology quiz.
How is Respiratory Control different from Renal Autoregulation?
Respiratory Control: The medulla adjusts breathing rate in response to blood CO2 and pH detected by chemoreceptors. Renal Autoregulation: Kidneys adjust arteriole resistance to keep glomerular filtration steady despite blood pressure changes. Read both side by side and note what each one explains.
How should I study Respiratory Control step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Renal Autoregulation and explain the difference aloud. Finally, take the Human Physiology quiz and come back to this page for any question you miss.