Biological complexity: automatic breathing controls (Introduction)

by David Turell , Tuesday, July 05, 2016, 18:07 (3063 days ago) @ David Turell

High or low oxygen and carbon dioxide levels control breathing at the base of the brain. Here is how:-https://www.sciencedaily.com/releases/2016/07/160705111905.htm-"There has been some debate over how the brain controls breathing. Now, a new study in mice, to be published in the journal eLife, shows that when exposed to decreased oxygen or increased carbon dioxide levels, the brain releases a small molecule called Prostaglandin E2 (PGE2) to help protect itself and regulate breathing.-***-"'Our novel brainstem culture first revealed that cells responsible for breathing operate in a small-world network. Groups of these cells work very closely with each other, with each group interconnected by a few additional cells that appear to work as hubs. This networking activity and the rhythmic respiratory motor output it generated were preserved for the full three weeks, suggesting that our brainstem can be used for long-term studies of respiratory neural network activity," explains David Forsberg, PhD student and first author of the study.-"'Secondly, we saw that exposure to different substances made the brainstem breathe faster or slower. Perhaps most interesting was its response to carbon dioxide, which triggered a release of PGE2. Here, PGE2 acted as a signaling molecule that increased breathing activity in the carbon dioxide-sensitive brainstem region, leading to slower and deeper breaths, or 'sighs'."-***-"The study also reveals a novel pathway linking the inflammatory and respiratory systems. PGE2 is released during inflammation and fever, which can dysregulate breathing patterns and interfere with normal responses to carbon dioxide. This can in turn cause disturbed and even dangerous halts in breathing.-"'Our findings go some way to explaining how and why our breathing responses to imbalanced oxygen and carbon dioxide levels are impaired during infectious episodes. It also helps further our understanding of why infection can inhibit breathing so severely in new-born babies," says Eric Herlenius, Professor at Karolinska Institutet's Department of Women's and Children's Health, and senior author of the paper."-Comment: Again one wonders how this develops stepwise by Darwinian theories. Note the brain produces chemical (hormonal) regulators as well as the resultant electrical signals, so we continue breathing without thinking about it. Also our breathing rate increases as we exercise and need more oxygen and to remove more CO2. Respiratory rate and heart rate move consistently in the same direction and have a ratio that is mathematically consistent with the degree of exercise. This is all accomplished by automatic feedback loops. Again I suggest saltation.