Final Thoughts on Vitamin B12 Injections. 1  Vitamin B12 injections (or shots) are used to overcome vitamin B12 deficiency, which is common especially among the elderly, those with intestinal damage or disorders, people with pernicious anemia, and vegetarians/vegans.
Neurons communicate over long distances by sending signals called nerve impulses through the axons which make up a tract or nerve. Because each axon may branch into a whole tree, and because nerve impulses go down each branch when an axon divides, a single neuron may send signals to thousands of other neurons.
Nerve cells use a variety of chemical messengers called neurotransmitters to communicate with each other. Neurotransmitters serve to carry messages between nerve cells by crossing the synapse, or space between nerve cells. Neurotransmitters also allow nerves to communicate with muscle cells in order to create motion.