The lumbar splanchnic nerves are a group of nerves that originate from the lumbar region of the spinal cord, specifically from the L1 to L3 vertebrae. They are part of the autonomic nervous system and primarily carry sympathetic fibers, which help regulate involuntary functions in the body. These nerves play a crucial role in innervating various abdominal organs, including the kidneys, ureters, and parts of the intestines. By transmitting signals, the lumbar splanchnic nerves help control processes such as digestion and blood flow, contributing to the overall functioning of the body's internal systems.