The other day I jammed my ring finger in a door. And the
few days after it was at a different temperature then the rest of my
fingers. I was wondering why. It was noticibly, to me, warmer.
Your finger was inflammed. The process of inflammation is part of your
non-specific immune response. This means that when a foreign substance or
injury happens, a series of reactions occurs. The signs of inflammation are
swelling, heat, redness and pain. To help healing your body sends out
chemicals to signal white blood cells and other cells to come to the area.
To speed this, the capillaries dilate to allow blood to travel to the area
faster. This causes swelling and the extra (warm) blood causes the warmth.
The cells also secrete substances called pyrogens ("fire-producing" in Greek)
that cause heat to be produced in the area. The extra swelling and pressure
can cause pain. So be assured that this is your body's built-in way of
helping you heal.
The first response your immune system makes to infection and damage is
inflammation and this is what you experienced. The same thing happens
when you contract a cold. It is the opeinng of capillaries and arterioles
of the damaged area in order to faciliate the non-specific immune
response. Flooding the area with blood will give the sensation of being
warmer. normally, your extrmeities are cooler becasue the blood is not
that near the surface of the skin.
Click here to return to the Biology Archives
Update: June 2012