The human body is more complex than we could imagine. Though we know what the human body is capable of, very rarely do we know why the human body does what it does.
Why holding your breath helps you stop hiccups?
Some theories propose that the hiccup is an evolutionary remnant of earlier amphibian respiration and in the process evolution and growth, it is an antecedent to modern lung respiration. When our diaphragm muscle involuntarily contracts, the human body tries to take a quick breath which is suddenly stopped by the epiglottis with the vocal cords snapping shut to check the inflow of air. This snapping is what makes the hiccup sound. Phrenic nerves serve the diaphragm muscle. Irritation of these nerve that stretches from the neck to the chest can also cause hiccups.
When you hold your breath, you build up carbon- di-oxide in your body that helps in stopping the diaphragm from spasming and in turn stops hiccups.
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Why do we yawn? Why is it contagious?
For the longest time we have believed that lack of oxygen is what causes us to yawn, however, more recent studies suggest otherwise. Research that studies yawning habits of people suggested that we yawn to regulate our brain temperatures. We yawn more often during summers, as opposed to winters. Inhaling oxygen can help cool down the brain temperature. It is surprising, the human body understands itself better than we do. The body yawn because it wants it to wake up. When we yawn, our lungs are stretched, joints and muscles and flexed and blood is forced to our face and brain, which increases alertness.
We yawn when we see someone else yawn, because we are in the same environment as theirs and exposed to the same temperatures. However, a yawn may also be triggered if you see people yawing in a video, even when they aren’t in the same environment as yours. Research suggests that catching a yawn is a sign of empathy and bonding.
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Why do we have eyebrows?
Though during the process of evolution human body hair reduced, however, eyelashes and eyebrows remained. This is because our eyebrows serve a purpose. They help us get a clear vision by preventing water, sweat and debris from falling into your eye socket. The shape and direction of the eyebrow hair channelizes the moisture to flow sideways around the eyes, along the side of the head. They also help to block out light and filter dust and dirt that may fall into the eyes.
Over a period of time, eyebrows have also begun to play a key role in the process of human communication. Eyebrows help in expressing happiness, anger, as well as surprise. Research also suggests that eyebrows may be a more recognizable indicator of identity.
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