Suppose we are standing or walking and we decide we want to run, how does our thinking finally turns into physical action of running? How does our neurons trigger muscular action ?
In: Biology
The idea for running is generated in the brain first. This happens in the motor cortex of the brain. It send nerve signals down into the spinal cord which then radiates to the muscles of the arms and legs. The spinal cord already has a nerve signal centre that allow for running. Individual muscles are stimulated but in a coordinated manner because of this spinal cord centre. So you don’t have to consciously move each muscle to start running.
I hope that explains a little of what you didn’t know.
I’m not sure how much detail you actually wanted so I gave a more general answer in my other comment which was more fitting for the sub. The more specific answer involves a form of energy called ATP which is made by metabolisation of food and stored. Nerves are fired using ions, sodium/potassium/calcium/chloride, ions carry electrical charge (they are charged particles) which travel along a nerve, a nerve is a type of specialised cell and they are joined together, surrounding nerves in the human body is something called a myelin sheath, this speeds up how quickly those electrical signals can be passed around. When the electrical inpulse arrives at the muscle, myosin filaments use the energy from the ATP to ‘walk’ along the actin filiaments. There’s essentially a ‘cross-bridge’ (imagine your fingers pushed together facing each other so that your fingers intertwine) and the walking action of one over the other causes the sarcomeres to contract (like your fingers pushing together), a muscle is made up of many sarcomeres together, forming a myofibril and are arranged tubularly into something called a sarcolemma, and many sarcolemma make up a skeletal muscle – which are only able to contract and relax and are the type of muscles involved in movement.
Other types of muscles like the heart (smooth muscle) work differently to the striated muscle found in skeletal systems
When you were a toddler you learned which muscles were involved in running and in which order you had to use them, you learned this by falling over a lot until you got the order right to stay balanced and upright while running. When you decide to run your brain just repeats that pattern by sending impulses down the nerves in the correct order and your muscles respond by contracting/relaxing in the correct order.
It’s essentially muscle memory, the same way you can drink from a glass or use a knife and fork, or type on a keyboard – at one point you couldn’t do it, eventually you figured it out, now your brain knows that action so well you can do it without much conscious input as far as moving each individual part/limb/digit
Try to do something you haven’t done before, and you can watch your finger be dumb for a while. Watch someone pick up a guitar and try to copy making a chord for the first time for example. They know what they want to do, they’re moving each individual finger but it isn’t going where you want it to. The only difference between that and running, is that we learned to run before we can even remember
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