The one thing that remains with us since our birth is our body. Since our childhood, we have spent a fair amount of time feeding it, nurturing it, fussing over it and gazing at it in mirrors. So, it would be logical to believe that we know our body pretty well. But do we? Actually, the human body is so complex that no one can claim that they know everything about their own body. Every day scientists are discovering new aspects of the human body. For example, do you know that along with helping in respiration, lungs can also make blood? Amazing, isn’t it? So, keep reading this article to find out 10 facts about the human body you probably never knew.
1. Lungs do more than help us breathe – a surprising discovery has found they also make blood.
Since our first biology class, we have been told that our lungs have one and only one job – to allow oxygen into our body and to get rid of the carbon dioxide from the body. In 2017, scientists discovered that lungs perform one other function. They play a key role in blood formation by assisting in the production of platelets. Platelets are an important component of blood. They stop bleeding by initiating and forming a blood clot. Before this discovery, it was believed that platelets were produced only in the bone marrow.
Scientists had the first inkling about the secondary function of lungs when many studies show that blood leaving the lungs had more platelets than blood entering the lungs. To investigate this, a research team led by Dr. Mark R. Looney of the University of California, San Francisco used intravital microscopy to study the lungs of a live mouse. They found that almost half of the total platelet formation occurs in the lungs. The study also revealed that when stem cells of the bone marrow are depleted, the blood stem cells of lungs are capable of traveling to the bone marrow to restore blood production. (1, 2)
2. Just like fingerprints, no two people have the same brain anatomy, a fact that was discovered by researchers of the University of Zurich. This uniqueness is the result of a combination of genetic factors and individual life experiences.
Our personal CPU, i.e. our brain, is similar to our fingerprints in one respect: no two are the same, not even in case of twins. This is a huge discovery as even 30 years ago it was believed that the human brain had few or no individual characteristics. This uniqueness of the brain has been discovered through a study by a group of researchers led by Professor Lutz Jäncke of the University of Zurich. In this study, Jäncke and his research team examined the brain of about 200 healthy, old people over a period of three years. Using an MRI scan, the researchers studied their anatomical features. They were able to identify a unique combination of specific anatomical characteristics for each brain.
The reason behind this unique brain anatomy is a combination of both genetic and non-genetic factors. Every event, even those performed for a short period, leave traces in the brain. Since every person has their own individual experiences, they interact with one’s own brain’s genetic makeup and, over the course of years, each person develops absolutely unique brain anatomy. (1, 2)
3. Neurons in human skin perform advanced calculations previously believed that only the brain could perform. Our touch experiences are already processed by neurons in the skin before they reach the brain for further processing.
The skin is one of the five sense organs of the human body. Everything we touch produces a sensation, and that information is carried to the brain through the nerves, or so we thought. Actually, it turns out that the information gathered by the skin is at first processed by the neurons of the skin.
According to a study by the researchers at the Department of Integrative Medical Biology, IMB, Umeå University, as soon as our skin comes in contact with an object, the neurons send a signal to the brain. Along with sending the signal, the neurons began processing geometric data about the object touching the skin. When we touch an object with our fingertips, the neurons gather information about when and how intensely an object is touched. It also processes information about the touched object’s shape. Researchers found that the neurons in the skin perform the same type of calculations as done by neurons in the cerebral cortex. So, even before the brain starts analyzing our touch, the skin neurons have calculated the required information about the touch. (1, 2)
4. Along with helping humans to see and distinguish colors and shapes, the rod and cone cells of our eyes perform a secondary function of burning glucose and converting the leftovers into lactate. Without this byproduct, the retina would die.
Rod and cone cells are one of the most important parts of the human eye. Also, they are extremely active and hence need lots of energy. For a long time, scientists have wondered as to how both these cells get their energy. The mystery has been solved after a decade of study by biochemist James Hurley and his colleagues at the University of Washington in Seattle.
The retina of our eyes needs glucose. This glucose is brought to the retina by a layer of cells beneath the retina called the retinal pigment epithelium (RPE). The RPE ferries glucose from blood to the retina but doesn’t keep any for itself. The study by Hurley and his colleagues revealed that the rod and cone cells of retina burn this glucose. The leftover is turned into fuel called lactate which is then fed back to the RPE. The mitochondria of the RPE burns the lactate and gets energy from it. That’s why the RPE ferries the glucose directly to the retina without keeping any for itself. If the RPE doesn’t get adequate lactate, it can switch to burning glucose instead of delivering it to the retina. Without glucose, the retina cells can die. (source)
5. Humans can “smell” with their tongue. Scientists have found that functional, olfactory receptors, the protein that binds to odors and aids the sense of smell in the nose, are also present in human taste cells found on the tongue.
During our childhood, we have been taught that a human has five sense organs among which is the nose for smelling and the tongue for tasting. But this general knowledge might soon be changed as scientists from the Monell Center have found that our tongue harbors a second sense other than taste. According to their findings, taste cells in human tongue contains olfactory receptors. Olfactory receptors are proteins present in the nose that detect odors.
According to this study, the interaction of the primary components of food flavor, smell, and taste, begins on the tongue and not in the brain as previously thought. Taste is the first step that helps in evaluating the potential toxicity and nutritional value of the food, while smell provides information about the quality of food flavor. Before this study, it was believed that both types of information are gathered in the brain where they are evaluated. But the presence of olfactory receptors in the tongue shows that both taste and smell interact in the tongue. Further studies are being conducted to understand how odor molecules modify taste-cell responses and affect human taste perception. (1, 2, 3)