How come there are some automated body functions that we can “override” and others that we can’t?

Question

For example, we can will ourselves breathe/blink faster, or choose to hold our breath. But at the same time, we can’t will a faster or slower heart rate or digestion when it might be advantageous to do so. What is the difference in the muscles involved or brain regions associated with these automated functions?

In: Biology

Answer 1

those functions have been outsourced to the autonomic nervous system because evolution has found this to be efficient to our survival.

from a contemporary human perspective we outsource simple and repetitive jobs to robots so we can focus our more expensive labor on problems that are more unique. so it should likely be this way with nature as well. the job of monitoring your blood pressure, body temperature and plasma salt and acidity levels etc, are essentially boring processes that can be dealt with without conscious intervention. this frees up brain power to deal with problems that are not repetitive such as, “how do I catch that rabbit for dinner?” as opposed to “our temperature dropped 0.1 degrees. turn up the metabolism!”

this is not to say that we cannot intervene in the mundane tasks of our bodies. there are recorded instances of people being able to control things like body temperature , blood pressure , even the dilation of their pupils without the typical external stimuli needed to effect such changes. but this requires extraodinary skill and free time. and what good does that serve to the species apart from entertainment?

years in the future when only driverless vehicles are allowed on the bigger roads people might ask “how come we can drive in some places but not others?” and I think the answer will be the same.

tldr
you can’t control some functions because your body has outsources them to automated systems millions of years ago. to try and intervene manually would both threaten your survival (you can’t be manually better than a robot which has been optimized over generations to do this job) as well as take precious brain power away from things that your species excels at (unique problem solving)