Explain why a person cannot hold his breath for a long time and even in a critical situation, for example

Explain why a person cannot hold his breath for a long time and even in a critical situation, for example, being under water, he will still take a breath

The medulla oblongata contains the respiratory center, which regulates the mechanisms of inhalation and exhalation. Its neurons (nerve cells) are very sensitive to the content of carbon dioxide in the blood. And with a long hold of breathing, its concentration in the body increases (since there is no exchange of carbon dioxide-oxygen) and neurons are activated, forcing to exhale / inhale.