Detta behandlas i Medicinska referenshandboken för Star Fleet , betraktad som en kanonkälla för information om fysiologin hos utlänningar.
HEART AND LUNGS
The Vulcan heart beats at the astounding rate of 242 bests per minute. The average blood pressure is 90 systolic, and 40 diastolic. This phenomenon is explained in part by the extremely dilated blood vessels of Vulcans. Large diameter blood vessels are an additional aid in cooling the body, allowing for greater cooling surface.
The Vulcan heart is located where one would expect to find the Terran liver, leaving room for the somewhat larger Vulcan lung assembly. In consequence, the cartilage that normally protects the Terran heart extends an extra 3.5 cm downward in a Vulcan in order to protect this vital organ.
