Question

Question #19aa7

Answer 1

The control is done by Neural Networks

Explanation:

Let us take the knee as an example.
For obvious reasons, only one muscle can be active at the time, the other will have to be inhibited so its tissue can be stretched.
The following picture is taken from "Neuroscience Online", a brilliant handbook from the University of Texas, and I thoroughly recommend having a look at it:
http://neuroscience.uth.tmc.edu/s1/introduction.html

The way it works: the afferent fiber (neuron) receives a signal, and excites the blue efferent (motor)neuron. this makes the Extensor Muscle contract. The Flexor Muscle though has to be inhibited otherwise, in the best scenario you would probably get cramp, worst case rip your muscles apart(?)
this is done by the black Interneuron, which, when excited by the green sensor, sends an inhibitory signal to the red neuron. this results in an IPSP (Inhibitory Post Synaptic Potential), which inactivates the Flexor Muscle....

With thanks to UTH Medical College....

PS this is anexample of a Reflex of course, as might have been deducted from the presence of the little hammer.

But think of the green neuron as instead coming from the brain/spinal chord, and the effect will be the same.....