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10 Lesser-Known Facts About the Human Body

Lesser-Known Human Body Facts

Discovering new facts about animals is fine, but it becomes quite strange to find new facts about ourselves. Novel discoveries about humans pose yet another question: is there more to know? And perhaps the answer is yes. As strange as the feeling might be, the facts are always highly interesting and never ceases to amaze us. From the whole bunch of these facts about humans, we’ve sorted the lesser-known ones. Stick to the below list until the end to know 10 lesser-known facts about the human body.

1. On average, humans have just as many hairs on their bodies as chimpanzees and other apes, but the difference is that on humans, they are a lot shorter and finer, which makes most of them nearly invisible.

Human hair
Human hair

Humans have often been called “naked apes,” and that serves us right because apparently, we don’t seem to have heavy coatings of body hairs like chimps and gorillas.

The fact of the matter is we do have the same density of hairs on our bodies, but what hair we have is a lot finer and colorless, unlike other apes that have them thick and dark. 

These short and fine hairs are technically known as “vellus hairs.” Scientists have attempted to answer two of the questions surrounding the discussion: why did we lose the thick hairs? And second, why do we still have the thinner ones, the vellus hairs? 

The agreed-upon answer is that it is the result of “half-hearted evolution” and the vellus hairs do not have any role at all.

However, some theories suggest other explanations. One of them suggests we have the vellus hairs to spot parasites. (1, 2)

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2. Our brains are the most energy-expensive organ in our body. They just make up an average of 2% of our bodies but consume 20% to 25% of our calorie intake. The percentage can rise as high as 60% in an average child aged from five to six. 

Human brain
Human brain

The major form in which our brain consumes a considerable amount of energy is glucose. The percentage of calorie consumption translates into 350 for women and 450 for men per day. 

Most of the energy is used by the brain to help neurons communicate with each other through the chemical structures called synapses, which are present between neurons. The most expensive process is the transportation of ions through these synaptic membranes. 

Scientists also say that the consumption of energy also increases when we are engaged in some highly difficult cognitive task like solving a crossword or when trying to learn something new like playing an instrument. 

Strangely, the mechanism of the brain using a high level of energy is not unique to just humans. The process has been discovered in very small mammals as well. (1, 2)

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3. Cilia are tiny, hair-like structures present in the mucus of our lungs, nose, and other parts of our body, and they spin in a particular direction. If the cilia start spinning in the opposite direction when you’re developing in the womb, your organs will literally get transposed to the opposite side of your body. 

Cilia
Cilia

That condition is called “situs inversus.” The condition is marked by reversing or mirroring the positions of all the vital organs compared to normal positions, nonetheless, the condition does not generally pose any health issues and is genetic.

After birth, the cilia move in a specific, given direction and also serve other functions of transporting the mucus and removing germs that can cause infections. 

Dysfunction in the movement of cilia causes infections and respiratory problems after birth, but cilia moving in the opposite direction before the birth will cause the transposition of the organs to the “other” side of the body than usual. 

There are three categories of situs inversus. The first is that in which all the internal organs are transposed. In the second, only the lungs and heart are mirrored. In the third case, the stomach, liver, and spleen are also transposed. The conditions are called “totalis,” “thoracalis,” and “abdominalis.” (1, 2)

4. Not just lions and zebras have stripes on their skin. Our skin is also covered with stripes of varied colors, but they are only visible under UV lights. The stripes are called “Blaschko’s Lines” and cover our bodies from head to toe. A few cases of genetic mutations can make these lines visible.

Blaschko’s Lines
Blaschko’s Lines

The stripes on the human body were first-ever discovered by dermatologist Alfred Blaschko in 1901, and thus the technical name “Blaschko’s Lines.” 

The lines are invisible in normal conditions, however, there are cases when genetic mutations make the stripes visible. 

Scientists say that the formation of Blaschko’s Lines happens when skin cells expand from the embryo into a baby. 

The lines are differently shaped. They follow the “V” shape on the back, swirl in the “S” shape on the chest and sides, and are wavy on the head. 

The lines are not useless. Doctors follow them down when doing surgery, and often cut and sew the skin following the lines. (1, 2)

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5. There is a unique, “free-floating” bone located in the root of the tongue called the “hyoid bone,” which is not connected to any other bones. The hyoid bone is held by muscles and ligaments that connect to other bones. It is considered as just an anchor of the tongue. 

Hyoid bone
Hyoid bone

This U-shaped bone can be found at the bottom of the tongue, in front of the neck, and between the lower jaw. The uniqueness of this bone is that it is not attached or articulated to any other bone in the body. It is attached to muscles and ligaments that are fixed to other distant bones.

The primary function of the hyoid is to provide a support structure for the tongue and assist in swallowing. While swallowing, the bone is constantly in a rapid upward movement along with the tongue and larynx. (1, 2, 3)

Also read: 14 Fascinating Facts About the Human Body

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