Body Phenomena Explained: Hiccups, Yawns, Goose Bumps & more
The human body is a complex powerhouse that is constantly buzzing with a plethora of activities. Breathing, blood circulation, replacement of dead cells, defense against germs, information processing, memory consolidation are just a handful of the myriad activities that the body performs at any instant. Yet, on the surface, it’s hardly noticeable that the body is working tirelessly to coordinate and perform these activities. However, in some instances, the outcome of these activities gives rise to observable and noticeable body phenomena such as goose bumps, burps, hiccups, coughs, yawns and more. However, most of us are quite unaware of what causes them and when trying to seek answers, the answers often range from the creative to the superstitious. For example, rumbling of the stomach is often linked to hunger, while hiccups are considered by some to be a sign that someone’s remembering you! In this article, we will explore some of these questions and their scientific explanations by looking at the behind-the-scenes body processes that lead to them.
Reasons behind common Body Phenomena
Why do we get goose bumps?
We have all experienced goose bumps at some point in our lives. Also known as goose flesh or goose pimples, these “bumps” develop on our skin when we feel cold or experience strong emotions such as fear, ecstasy or sexual arousal. Goose bumps are formed by the contraction of the muscles at the base of hairs, making the hairs erect. This phenomenon occurs in many mammals besides humans. As a response to cold, the erect hairs trap air and create a layer of insulation, thus keeping the body warm. The emotional stimuli, however, is more useful to animals than humans as a defense mechanism since the erect hairs make the animals appear larger and thus, intimidate their predators.
Why do we burp?
Burping is often frowned upon and can be a source of embarrassment in social or professional settings. And although it seems gross, burping is a perfectly natural body phenomena. While eating or drinking, we tend to swallow air which leads to an inflated stomach and abdominal discomfort. To relieve this discomfort, the swallowed air needs to be expelled. Burping, also known as belching, is the expulsion of the swallowed air from the digestive tract through the mouth. The expelled air is primarily a mixture of nitrogen and oxygen. However, in burps arising from drinking carbonated beverages, the primary gas expelled is carbon dioxide from the beverages themselves. Other causes of burping include acid reflux and gastritis.
What causes the sound when we crack our knuckles?
Many of us tend to crack our knuckles when we are tense or anxious or sometimes, just to pass the time! It often makes us feel relaxed and is sometimes used by chiropractors as part of joint adjustment routines. But what produces the cracking sound? While several theories have been put forth, most recent evidence suggests that when you crack your knuckles, the joints get stretched and bubbles are formed in the synovial fluid that flow in the joint cavities as dissolved gases leave the solution. The formation of the gas bubbles (mainly carbon dioxide) results in the cracking sound we hear. And while many believe that cracking of knuckles can result in arthritis, there is no conclusive evidence yet to prove this claim.
Why do we sneeze?
Often following a running nose or viral infection, sneezing can be both a relief and a pain. However, from the body’s point of view, it is a natural reaction to irritation to mucus membranes of the nose and throat caused by allergies, foreign particles and infections. The function of a sneeze is to expel mucus containing these irritants and cleanse the nasal cavity. It is an involuntary activity that may also be caused by sudden exposure to bright light (the condition is known as photic sneeze reflex), sudden changes in temperature or in some rarer cases, even on a full stomach (known as stomach sneeze reflex or snatiation).
Why do we cough?
Another friend of colds and viral infections, coughs are responses to irritation to the respiratory passages caused by foreign particles, fluids, secretions and microbes. The function of cough, just like a sneeze, is to clear the respiratory passages by forcefully expelling the air containing the irritants from the mouth. Unlike sneeze though, coughs can be voluntary, meaning that you can force coughs on your own as we often do to feign illness! Coughs can also be caused by other factors such as choking and smoking.
Why do we get hiccups?
All of us have been through the series of “hic” sounds at some point in our lives. Hiccups (medically known as synchronous diaphragmatic flutter) are involuntary contractions of the diaphragm causing sudden intake of air followed by the closure of the vocal cords , resulting in the “hic” sound. While scientists are yet to reach a definitive conclusion on the mechanism leading to hiccups, some circumstances have been associated with a higher chance of hiccups such as sudden temperature changes, rapid intake of food, spicy foods, intake of carbonated beverages and acid reflux. In most cases, hiccups resolve on their own once the diaphragm relaxes.
Why do we yawn?
Stifling a yawn in boring meetings or when you are sleepy in a classroom is rather tricky business. But what really happens when we yawn and why do we yawn? When we yawn, our mouths are wide open, thus allowing for maximum air intake. The inhaled air expands the lungs to capacity, flexes the abdominal muscles and pushes the diaphragm down. This is then followed by an exhalation of breath. Several theories have been proposed to explain why we yawn, but 2 popular theories are: 1) it is a mechanism to cool the brain by removing “hot” blood from the brain and introducing “cooler” blood from the lungs, and 2) it is a social empathetic mechanism, which probably explains why they are contagious. It is also commonly associated with boredom or fatigue.
What causes the “pins and needles” (or limb “sleeping”) feeling?
Paraesthesia or the “pins and needles” feeling is a tingling, numbing or pricking sensation felt in the arms, legs or feet. It is what many refer to as limb “falling asleep”. In most cases, it is temporary and doesn’t cause any pain. It is caused by the application of pressure on a body part by leaning or resting or putting weight on it. The applied pressure cuts off the blood supply to the area temporarily and restricts nerve impulses, thereby preventing the nerves from sending important signals to the brain. The numbing feeling usually eases when the pressure is removed and blood supply is restored. Most people experience temporary pins and needles occasionally but if it’s chronic, it might be an indication of improper nerve functioning or poor circulation.
Why does our stomach rumble?
Ever been in an important conversation or meeting and trying to fight off your stomach noises? Although awkward and embarrassing at times, stomach rumbling (also called abdominal or bowel sound) is a perfectly natural and ongoing phenomenon. The noises are produced due to the muscular contractions of the intestinal wall as food and air moves through it. The walls contract to mix and squeeze the food through the intestine and aid digestion. This process, called peristalsis, occurs for most of the day and so do the rumbles, though most of the time they aren’t loud enough to hear. The noises are loudest when the stomach is empty, hence are often associated with hunger.