10 Interesting Facts About Human Biology

The human body is incredible. It is a unique system of interrelated structures and essential organs that work continuously to perform the duties required for daily life. For instance, your mouth, esophagus, stomach, and small intestines combine to digest your food and give you the nutrients needed to keep you in good health. 

While most of us know the essential physical functions that keep us alive, you may be unaware of some of your body’s amazing capabilities. This article comprises a list of 10 intriguing facts about the human body. 

1. 200 Million Human Skin Cells Are Lost Every Hour

Your skin develops rapidly. About 200 million skin cells are shed every hour. Your epidermis (top skin layer) constantly replaces the dead cells. 90% of these layers contribute to the formation of new skin cells, while the other 10% create melanin, the pigment that gives skin its color.

2. Your Gut Has a Separate Nervous System

All the organs that collectively comprise the gastrointestinal system (gut)—liver, pancreas, stomach, small intestine, colon, gallbladder, and rectum—are often referred to as the ‘second brain.’ It’s the only organ in the body with its own neural system, which comprises 100 million neurons buried in the gut wall. Neurons act as transmitters in your nervous system. They send signals to muscles, nerve cells, and gland cells all over your body.

This second brain is so strong that it can keep working even if the main neural link between your gut and your brain is cut. This means that, even if your brain couldn’t connect with your gut, neurons in your gut wall can still transfer the information needed for your digestive system to function independently.

3. Your Heart Rate and Breathing Can Sync to the Music You’re Listening to

The songs you listen to affect your blood pressure, pulse rate, and respiration. According to studies, changes in the respiratory and circulatory systems caused by listening to music immediately reflect the rhythm and intensity of the song.

For example, songs’ crescendos (rises in intensity and volume) can cause corresponding rises in blood pressure, heart rate, and breathing. Decrescendos and silent periods, on the other hand, cause a drop in these vitals. Repeated rhythms can also drive your system into sync with the beat.

4. Bacteria in Your Gut Can Influence Your Mood

The collection of bacteria in your stomach is known as your microbiome. This bacterial colony can affect neurological development, behavioral patterns, sensory abilities, and stress levels. 

At birth, your gut is clean. Over time, your GI tract becomes colonized by various bacterial species, influenced by your genes and environmental exposure.

The microbiome produces hundreds of neurochemicals, which your brain uses to govern memory, learning, and temperament. Your microbiome creates nearly all the serotonin in your body, a key hormone that regulates your mood, emotions, and happiness. Serotonin helps treat depression, anxiety, and poor bone health. It also helps people sleep, eat, and burn calories.

5. Your Brain Shrinks During Pregnancy

Pregnant women have lower cortical thickness and surface area in grey matter areas of the brain, according to a 2017 study published in the Nature Neuroscience journal. This finding gives the phrase “pregnancy brain” a whole new meaning. The cerebral cortex suffers the most from grey matter loss, particularly in areas that regulate thinking skills and where we interpret emotions and nonverbal messages. However, rather than being harmful, this volume reduction helps the brain understand social circumstances more quickly, especially when figuring out what babies want and how they feel.

6. Tattoos Do Not Stay on the Human Skin 

Given that we shed our skin cells constantly, why do tattoos not wipe off? Well, the answer is that the ink does not stay in the skin but goes into your immune system. A type of white blood cell known as a macrophage tries to heal the injury around the tattoo and remove the foreign substance. However, they cannot remove the ink, so they “eat” it and remain positioned to guard the skin. When these cells die, new macrophages take their place and repeat the process, which is why the tattoo remains visible.

7. Your Blood Vessels Would Extend for More Than 60,000 Miles From End to End

The circulatory system, made up of arteries, veins, and capillaries, is responsible for circulating blood throughout the body. These vessels make sure blood is available in every part of your body. Arteries carry oxygenated blood away from the heart, while veins return deoxygenated blood to the heart. Capillaries connect arteries and veins.

The huge network of blood vessels would stretch for approximately 60,000 miles if placed end-to-end in an adult, and somewhat less in a child. Your capillaries, the tiniest blood vessels in your body, would account for roughly 80% of this length. 

8. Your Cornea Lacks Blood Vessels 

The cornea is the transparent part of your eye that protects the pupil, iris, and anterior chamber. The cornea’s transparency lets light flow through to the retina and then to the brain, where it is processed. The cornea is transparent because, like cartilage, it does not contain blood vessels.

9. Fingernails Develop Faster Than Toenails

Fingernails grow faster because they are exposed to sunlight more frequently. Also, the nails on your most active hand grow more quickly than those on the other hand. The longest nail is usually found on the middle finger. Generally, the size of the nail and the size of the finger are in direct proportion. 

10. Babies Do Not Shed Tears Until They Are at Least a Month Old

Experts have confirmed that it is possible and perfectly normal for babies not to shed tears for up to the first three months. This is because their tear ducts are still developing at this time. Certain babies have blocked tear ducts, which means they can cry, but their tears don’t flow properly.

However, a sticky yellow discharge caused by collected tears can be managed with drops or ointment prescribed by your doctor. They will also demonstrate how to wipe your child’s eyes and, if necessary, soothe the tear duct.