Sympathetic nerves in the lower body. Historical anatomical artwork of a side view of a dissected human abdomen and chest, showing the origin and route of parts of the sympathetic nervous system. This system is responsible for triggering energy production by the body, especially in emergency situations. Nerves (white) are seen branching out across the body from ganglions near the spine (down left). One function is the ennervation of the heart (top centre). A kidney (centre left, brown), its adrenal gland (yellow), the main body vein (blue) and body artery (red) and the bladder (bottom) are also seen. Artwork from The Nerves of the Human Body (Ed. Jones Quain, London, 1839).