The human sensory system is not just limited to the nerves, according to new research that has discovered a hidden sensory network throughout the blood vessels and glands.
As recently detailed in the journal Pain, researchers studied two patients with a rare condition called congenial insensitivity to pain, which is marked by an inability to feel most pain.
Analysis of skin biopsies from these two patients revealed normal nerve endings associated with skin sensation to be missing, thus explaining why these patients were unable to respond to different types of temperatures and mechanical contact, providing just a few examples of their sensory impairments.
Yet these patients were still able to tell what was hot and cold in addition to maintaining other adequate sensations for daily living, leaving researchers wondering how they felt anything.
According to the researchers, these patients are able to feel things due to sensory nerve endings on the small blood vessels and sweat glands in the skin.
Originally, such nerve endings were thought just to regulate blood flow and sweating, but now are being associated with providing sensory feedback that is barely noticeable in most people but certainly conscious in the patients lacking normal nerve endings.
Based on their findings, the researchers noted how problems with these hidden nerve endings may be related to migraine headaches and fibromyalgia, conditions whose sources are unknown and whose symptoms are difficult to treat.