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
This may be explained but I’ll add
The body have two defences so to speak. What you can consciously do and what you cant.
You can consciously tell your body to breathe or walk or blink. But the body can also handle these without your input, else we would spend every second thinking like this
“Step, step, breathe in, step, blink, step, breathe out,” you would never get anything done. It would be huge strain on the brain.
Also, the second defense is at a local level. By this, as someone has explained the heart has it’s own nerve system and pacemaker, that doesn’t need a brain to control. Which is why when someone “dies” the heart can actually be restarted, and sometimes bring them back, or sometimes the person is brain dead but the heart can live.
Which is why a heart transplant can be done. The organ can control it self.
Another example is the spine. If you stub your toe , what happens is the toe senses danger, that travels up the foot, up the leg and into the spine. Now instead of going to the brain only, the spine will tell the leg to pull away quickly, in doing so it also knows to throw your weight to the other leg to balance. All that is done without a brain!
There was a study done, nasty to see. Where they cut the brain stem of a cat, and put it onto a treadmill. The “dead” cat was able to walk and step over a hurdle, all without any input from the brain.
You may have heard of the headless chicken? True story. No brain, but it lived based purely on body reaction alone.
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