Skin Sensitivity and the Cold
A student in my anatomy and physiology class asked me, "When
it's very cold outside in the winter, why does your skin hurt MORE than
usual when you bang your finger or someone slaps you on the arm?"
Wow! This is one outstanding question.
Mammals respond to cold weather with the hypothalamus releasing thyrotropin
releasing factor. This production increases with the severity of the cold
weather and the length of the exposure to cold over a long period of time
(at least three to four weeks). The thyroid responds by slowly increasing
in size and releases thyroxine at higher quantities. Thyroxine increases
the sensitivity of the entire nervous system. As a matter of fact, as you
probably know, it increases the metabolism wholesale! within the
body. This gets complicated so I'm keeping it simple. So, the bottom line
is thyroxine. It just heightens our sensitivity not only to cold but our
entire nervous system is enhanced.
Click here to return to the Biology Archives
Update: June 2012