Highway to the Heart
Jesse Ashton, Doctoral Candidate
A busy highway of nerves connects the brain with the heart, conveying messages as electrical impulses at break-neck speeds to ensure the heart always pumps enough blood whether one is walking or running.
The straights, bridges, off-ramps, and on-ramps you can see are made up of nerves that are less than one tenth the width of a human hair traversing a small volume of muscle.
The lights sit at junctions where nerves - when necessary - pass on their cargo of the neurotransmitter noradrenaline and thereby provoke surrounding muscle cells to beat harder. Bright spots are like street lamps on roads close to the surface; dim spots, lamps on distant streets deep in the volume.