1. (Brain) Precentral gyrus: the origin of nerve signals initiating movement.
2. (Cross Section of Spinal Cord) Corticospinal tract: Mediator of message from brain to skeletal muscles.
3. Axon: the messenger cell that carries the command to contract muscles.

4. Neuromuscular junction: the messenger axon cell tells muscle cells to contract at this intersection
Own work
Isa.tomanelli