If nerve cells are up to 1 meter long, why can't we see them?

You can see that most of the neurons are at most 10 micrometers thick. That's really thin for a human eye to see. As a fun fact, we can see Squid giant axon because they're about a millimetre thick. Here's an image with human hand to scale. read more

It is long so it can connect with other nerve cells from a distance and it is branched so that it can create connections (synapses) with multiple different nerve cells at the same time. read more

Neurons are nerve cells, or cells found in the nervous system. These are specialized cells designed to stimulate other cells in the body in order to communicate. Neurons are excitable, which means they function by using electrical stimulation. read more