That's what is called competitive enzymatic regulation. If there are more of that substance than the enzyme substrate, then most of the enzyme, if not all depending on the substance's concentration, will be inhibited on its action. If there are more substrate then the competitive substance, the expected reaction for that enzyme will happen at an expected rate. If the ratio substrate:substance is 1:1 then the reaction enzyme-substrate is very slowed down.
The central communication conduit
between the brain and the rest of the body is the spinal cord. The spinal cord
is a long thin structure that comes from medulla oblongata in the brain stem to
the bottom of the spine. The spinal cord is made up of nerves that transmit messages
between the brain and the rest of the body.