system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How are nerves connected throughout the body and why do two distinct places on the body sometimes feel connected?
gpt
Nerves aren’t really connected to each other. Sensory nerves run from your skin (or organs), and travel to you spine. The path they take from there is unique depending on what information the nerve carry’s (pain/temp or light touch/proprioception/vibration are the rough groups in your spine). The second neuron travels up your spine and synapse onto a part of your brain called the thalamus. The third neuron travels from your thalamus to the cortex of your brain. On the surface of the cortex, theres a “map” of your skin, so all of the information from your fingertips go to one place, your lips go to another, your toes go to another. It’s not always obvious which ones are next to eachother (for instance genitals are next to feet and lips). Sometimes there can be spillover of the nerve impulses - maybe why kissing is a sexual thing (and maybe why foot fetishes exist). 

There can also be referred pain - for example a heart attack can cause pain in your shoulder. This is because the nerves that give sensation to your heart and your shoulder come from the same part of your spine (specifically C4 vertebrae iirc), so there can be spillover of the signals.