Have you ever had goosebumps because of fear, when entire body hair is raised? Discover the five stages through which our body passes when we are faced with something scary.
Dr. Sherry Hart, an assistant in neurology at Ohio University and Dr. Vesna Petronikj-Rosic, a dermatologist at the University of Chicago, explain what happens to us when due to fear the body hair raises.
- The alarm is activated
When your amygdala (part of the brain involved in processing emotions) recognizes danger, even if it is an imagined danger (when you watch a horror movie), it sends a signal to the control center – the hypothalamus.
- Increased adrenaline level
The hypothalamus activates the sympathetic nervous system which makes your body to react- fight or run.
Your adrenal gland is activated, so it starts to pump out large amounts of adrenaline into the bloodstream, which leads to rapid heartbeat. At the same time, the nerve endings in the skin release the hormone noradrenaline.
- Defensive reaction is activated
The brain is working fast; the breathing is accelerated, as well as the heart beating which increases the circulation and adrenaline quickly spreads throughout the body. It reaches the layer of skin known as the dermis where adrenaline and noradrenaline act together.
- Muscles contraction
Among the organs that are activated due to defense reaction, are muscles known as arrectores pilorum. These are small muscles which are attached to hair follicles. Adrenaline and noradrenaline control these muscles and cause contractions until the danger is gone.
- You get goose bumps
The contraction of these muscles results in body hair rising and in appearing of small bumps on the skin.
This reaction is developed through evolution and we share it with other mammals, such as cats or porcupines, only they look bigger and more dangerous.