Hair Raising – It Will Give You Goosebumps
Hair erection is the technical name for what most of us know as “goosebumps”. It is the disorder that happens in the hair follicles when we are cold, elated, shocked or scared. There is also a neo-Latin clinical term for it: Cutis Anserina.
Researchers say that hair erection is an evolutionary relic that reminds us of the texture of a bird’s skin after picking its feathers. Humans inherited this trait from our ancestors, who also got goosebumps when they experienced extreme sensations.
For example, cats have a similar reaction. Their hair rises when they sense danger and prepare to fight or flee. They also shoot back and become more aggressive, which is somewhat reminiscent of how other animals react.
What is hair straightening exactly?
Hair erection is an involuntary physiological phenomenon triggered by an action in the sympathetic nervous system. The muscles for hair erection contract so that the hairs stand up, thus giving the skin the characteristic appearance reminiscent of a bird that has had its feathers plucked.
What happens is a contraction of the small muscles at the base of each hair. It opens them up so that the hairs become separated and stand up and give the skin the grainy look. This usually happens on the forearms, legs, neck, head and neck.
It occurs under all sorts of stimuli, such as:
- Shock
- Fear
- Overwhelming emotions
- Excitement
Most of the time, but not always, there is a slight drop in body temperature when we get goosebumps.
Anatomical and biological aspects
As we mentioned above, hair raising is a reaction in the sympathetic nervous system. This is also known as the adrenergic or noradrenergic system. And this name is due to the fact that norepinephrine is the primary neurotransmitter here.
The sympathetic nervous system is activated during certain situations, such as escape, stress, exercise and emergencies. The adrenal glands release adrenaline, which enters the bloodstream in this type of situation. Hair erection therefore takes place. It also increases the activity of the muscles and makes us shake so we can warm up again when produced by cold temperatures.
If the goosebumps are the result of fear, hair growth will occur along with an increase in heart rate. This leads to more blood being pumped to the large muscles and the pupils being dilated to improve our vision. Something similar happens in case of shock and overwhelming emotions.
The function of hair erection
The mechanism of hair erection is present in many animals with fur. When the hairs rise as a reaction to cold temperatures, it is just a reflex. Hair that stands up allows air to be trapped and create a layer of insulation that helps protect against low temperatures.
When goosebumps occur as a reaction to fear, its role is to increase body volume. In other words, we seem bigger when the hairs stand up, and thus more intimidating. As you can see, this is a biological defense mechanism that is activated when we feel threatened.
Hedgehogs are the best example to illustrate the function of hair raising. This animal raises its spikes when they sense danger. The same thing happens with many other mammals, such as chimpanzees, mice, cats, etc.
Other interesting information
In conclusion, hair raising in humans is basically useless. We do not have enough hair on our bodies for it to really act as an insulating layer. Likewise, our hair is not long enough to make us look bigger than we are when we get goosebumps.
This is why scientists believe that this phenomenon is solely a remnant of our evolutionary process. That means we inherited this defense mechanism from our ancestors, but we cannot use it like other mammals do.
First, the human brain is much more complex than that of the other species, and the reflex with hair-raising is also governed by psychological factors. Our limbic system makes our hair stand on end when we hear a song we like or the voice of someone we love.
