Human Body Facts

The blood in the human arteries is a bright red while the blood in human veins is dark red.

The red color of our blood is due to the hemoglobin inside our red blood cells. Hemoglobin is a protein that makes up a complex iron molecule that transports oxygen in our system. Iron has a certain property that reflects red light, which is why we see blood as red.

You cannot sneeze with your eyes open.

This is because of the pressure that comes from the sneeze. The body’s blinking response is active during a sneeze to protect the eyes from any germs. Some people believe that we close our eyes when we sneeze to keep our eyeballs from popping out. This is not true.

A person is unable to detect smells when they suffer from anosmia.

There are rare cases in which a person may be born with anosmia. This condition is congenital anosmia. A loss of smell could also mean no sense of taste.

Bromidrophobia is the term used for the fear of body odors.

Psychologists link this with obsessive-compulsive disorders (OCD). With OCD, it details the washing itself. Bromidrophobia focuses on removing the smell itself.

Cerumen is the medical term used to refer to ear wax.

Earwax is a brown or yellowish substance that the ears secrete in the ear canal. This protects the skin of the human ear canal against bacteria, water, and insects. Earwax also assists in keeping the ear clean and lubricated.

Borborygmus is the sound your stomach makes when you are hungry.

This sound is due to the movement of fluids and gasses inside the intestines. This is a normal phenomenon that anyone experiences. If you are not hungry, this could be a sign of incomplete digestion.

The average person has around 250 hairs per eyebrow.

According to research, those who do not or have never plucked their eyebrows can have as many as 1100 total hairs. On average you lose about 10 eyebrow hairs a day. The hair in this area can grow back so long as there is no extensive damage to the area.

Fingers don’t have muscles that help movement.

The muscles that move the fingers are the palm and forearm. The long tendons that deliver motion from the forearm muscles can be seen under the skin by the wrist. You can also see muscle movement from the back of the hands.

Fingernails grow approximately 3 millimeters per month which is twice as fast as toenails.

If you were to lose a fingernail, it would take approximately six months to regrow it completely. On the other hand, it takes a toenail around 12 to 18 months to completely regrow.

There are over one hundred thousand hairs found on the average scalp.

Each hair from a person’s head grows from a single tube-like hole. This hole is a follicle. Hair sticking out of the skin is the hair shaft.

The human ears and nose do not stop growing.

After puberty, your muscles and fat cells also stop dividing. As you grow older, your earlobes also elongate from gravity. This is why older people often have bigger ears and noses.

Messages from the human brain travel along nerves at a speed of 200 mph.

Signals to the human brain can travel as slow as 1 mph or as fast as 268 mph. An axon delivers messages via chemical and electrical impulses from the body. The fastest nerve impulses ever recorded can travel at 288 mph.

The femur is the largest bone located in the human body.

The head of the femur fits into your hip socket and the bottom ends of it connect to your knee. More commonly, we call this bone the thigh bone.

The human body has over 35 trillion cells.

If the Earth has about 7 billion people, that means that there are 5000 times more cells in the human body than there are people on the planet. Although this number will vary depending on a person’s overall build and health.

Having chromesthesia allows you to hear colors.

This is a type of synesthesia in which heard sounds are automatically and involuntarily evoke an experience of colors. Famous artists such as Vincent van Gogh, Franz Liszt, and Billy Joel all have chromesthesia.

The Uvula translates to grape in Latin.

The Uvula is a fleshy extension that hangs down from the back of the soft palate of the mouth. The function of this is to close off the passage of the nasopharynx when swallowing.

This prevents food from entering the nasal cavity. The thin saliva it produces is also said to keep the throat lubricated and has a function for speech as well.

A passionate kiss can cause the same chemical reaction as skydiving.

The dopamine released during a kiss and stimulates certain areas of the brain. As a result, we experience feelings of great euphoria and addictive behavior. An intense kiss can trigger the same adrenaline we experience when doing something extreme and exciting.

Check out more juicy sex facts you’d want to know.

Your dead skin ends up in the atmosphere.

An abundant amount of dead skin comprises billions and tons of dust in the Earth’s atmosphere. Research has shown that dead human skin helps clean the air. This is because the dust from dead skin has oils that can clean the ozone.

The little finger contributes 50% of our hand strength.

The little finger along with the ring finger act as a power bottom. The thumb, index finger, and middle finger provide dexterity. The pinky finger is the most important part of your have to maintain a strong grip. If you were to lose a finger, doctors suggest the index finger is the best one to lose.

Check out this article on how our finger names came about! 

The human genome is extensive.

Its total length is over 3 billion base pairs of DNA and is organized into 22 paired chromosomes. If a person had a typing speed of 60 wpm maintained at 8 hours a day, it would take them over 50 years to complete typing the human genome.

Our skeletons renew themselves.

After the body’s skeleton grows and forms into its adult size, it then regenerates itself every 10 years or so. This is remodeling and is a process in which it removes old pieces of bone and replaces them with fresh new ones.

The word muscle means little mouse.

This came from the Latin word musculus. The Romans thought that flexing a muscle looked like a mouse was moving underneath the skin.

The thighbone is the longest bone in the body.

This measures about 18 inches or 46 cm long. However, this is only so in an adult’s fully grown skeleton. The shortest bone in the body is in the ear which is shorter than your average grain of rice.

Don’t miss this article to find out more about the longest bones in our human body! 

You would not be able to count the number of nerve cells in the human brain in one lifetime.

Because of the large number of brain cells the human brain has, scientists say that it would take over 3000 years to complete counting.

The human bone is stronger than steel.

If you were to have a bone and a piece of steel of the same length and thickness, a bone would be five times stronger than the steel bar. However, bones are brittle and can also fracture on impact.

Only 12% of the population is left-handed.

To this day, only 12% of the total population in the world is left-handed. 87% of the population is right-handed and the remaining 1% being ambidextrous (that’s really cool!). Even though it is becoming more socially acceptable, some parents still train their children to write using their right hand.

The bumps on your tongue are not the taste buds.

In reality, your actual taste buds are so tiny that you cannot see it with your naked eye. The bumps that you see on your tongue are the papillae which are sensory organs. These rest on top of the taste buds. The taste cells in our taste buds also live for two weeks before new ones replace them.

A person’s foot has an average of 500,000 sweat glands.

Your feet are capable of producing a pint of sweat a day. This is why you should always wear fresh socks to prevent the build-up of bacteria on your feet. The foot also accounts for 25% of the bones in the human body.

In one lifetime, a person produces 25,000 quarts of saliva.

To give you an idea of how much saliva this is, this amount is enough to fill two average-sized swimming pools. However, your saliva is mostly recycled rather than produced. This is because you are constantly swallowing and absorbing it. The human body produces about 30 ml of saliva in an hour.

Your eyelids have the thinnest amount of skin on your body.

The levator palpebrae superioris muscles retract the eyelid which exposes the cornea and gives you vision. The eyelids can move both involuntarily and voluntarily. On the other hand, the feet have the thickest amount of skin on the body.

The only organ in the human body that can completely regenerate is the liver.

The original liver mass can regenerate back to its full size even if it lost less than half of its original mass. Unlike with other organs such as the heart, a scar replace damaged tissue. The ability of the liver to regenerate is due to the central liver homeostasis.

An adult’s step takes up a lot of muscle movement.

To be precise, the human adult body uses up about 200 muscles to take just one step. The muscles included in making walking possible are the quadriceps, hamstrings, buttock muscles, stomach muscles, calf muscles, and several other secondary muscles. Two main joints are also used to be able to take a single step.

The space between the eyebrows has a name.

Its name is the glabella. It’s from the Latin word glabellus. This word directly translates to smooth. Clinically, this area is a basis for measuring how dehydrated a person is.

The average human processes 100,000 pounds of food in a lifetime.

That is approximately 35 tons of food in a lifetime. Apart from food, the average person will also ingest about 100 milligrams of dirt every day. This roughly equates to six pounds of dirt in an average lifespan.

An adult human’s blood circulates about 12,000 miles a day.

To give you an idea of what this is like, imagine traveling from east to west across the most unstable parts of the Pacific Ocean. The pulse you feel is the blood stopping and starting again as it moves through your arteries. About 5.6 liters of blood circulates through the body a total of three times every minute.

In a lifetime, the average person walks 100,000 miles in total.

This is equal to walking around the world a total of four times on the line of the equator. This is also around 160,934 kilometers long. A healthy person is capable of walking 20–30 miles a day without stopping. Many trained walkers can finish a 26.2-mile walk in a total of seven hours on average.

Humans consume a lot of water.

Water is a major part of most life forms and cannot survive without it. By the time humans reach the age of 70, they would have consumed about 12,000 gallons of water. Water is the best and most hydrating liquid that promotes cardiovascular health.

The lining of your stomach replaces itself constantly.

Every 4 to 5 days, the lining of your stomach replaces itself. This is to prevent the stomach from digesting itself. The stomach cells that have come into contact with food that is digesting replace themselves every 5 minutes. Intaking probiotics can help any other damages that your lining may experience during digestion.

The lifespan of eyebrow hair lasts an average of four months long.

This means that this is the average time it takes for the hair to fall out and grow back. Research has also shown that over-plucking your eyebrows could affect its growth and keep it from reaching its full lifespan. You can also speed up eyebrow hair growth by applying a coconut oil massage.

Emetophobia is the fear of vomiting.

This particular phobia can include subcategories. Different types of anxiety, including fear of public vomiting, seeing vomit, or watching the act of vomiting can trigger those who have emetophobia. It comes from the Greek word emein which means to vomit.

Our bum crack is medically referred to as the intergluteal cleft.

The crena is another formal term used for the cleavage of the buttocks. We have butt cracks mainly due to the preliminary muscles that sit inside the evolved pelvic bones.

Four-legged animals also have these muscles and use them for pushing forward when running.

The gluteus maximus is the largest muscle found on the human body. This is a large and powerful muscle that keeps the trunk of the body in an erect posture. This muscle is also the reason why we can easily climb up the stairs. The human buttocks have three main muscles.

The reproductive system allows humans to reproduce.

The males produce sperm which fuses with the egg cells of the females. This is then fertilized and implanted in the woman’s uterus. After some time, the egg grows into its fetal stage which eventually turns into a human baby.

The urinary system allows the human body to expel waste products called urea.

This substance forms when foods break down inside the body. This system includes the bladder, kidneys, and sphincter muscles.

Humans have five vital organs in total.

Without any of these organs, a human being cannot survive. These organs include the heart, lungs, kidneys, liver, and brain. Among all of these, the brain is the most important organ in our bodies that we must take care of.

The immune system exists to defend our bodies from bacteria.

This system consists of lymph nodes, the spleen, bone marrow, and lymphocytes. This also includes our white blood cells and thymus. All of these components are capable of dealing with different levels of bacteria.

The muscular system consists of 650 muscles.

These muscles aid us in movement, blood flow, and bodily functions. In this system, there are 3 kinds of muscles. This includes skeletal muscle, smooth muscle, and cardiac muscles.

206 bones make up the skeletal system.

However, newborn babies are born with more bones in their bodies that only develop later on as they grow. Tendons, ligaments, and cartilage connect these bones. The teeth are also part of our skeletal system, but they are not considered bones.

The brain functions as the control center of the human body.

This organ is in charge of receiving and sending signals throughout the body. It makes use of the nervous system mainly to send signals and also uses secreted hormones. The brain handles a person’s thoughts, emotions, and memory. It also controls a person’s general perception of the world around them.

The lungs remove oxygen from the air we breathe.

It also transfers the oxygen to our blood which carries it to the cells in our bodies. The lungs also remove carbon dioxide that we exhale. While it is better that you keep both of your lungs healthy, you can technically live with only one lung.

The largest lymphatic organ in the body is the spleen.

This is on your left side under the ribs. This organ contains white blood cells that fight against infections or diseases. The spleen also helps control the amount of blood in the body and disposes of old or damaged blood cells.

The body’s bone marrow produces white blood cells.

This is the yellow-colored tissue found in the center of bones. The spongy tissue inside some bones such as the hips and thighs contains immature cells. The human body replenishes the bone marrow as it does with blood. This also means that you cannot sell it for as much as you could with a kidney or any more valuable organ.

T-cells mature in a small organ called the thymus.

This is often overlooked as a part of the immune system. The thymus is beneath the breastbone. It can trigger and maintain the production of antibodies. The thymus is also found to be larger in infants than in adults.

Brushing your teeth too hard is bad for you.

Doing so can wear down the enamel. This would then make your teeth sensitive to hot and cold foods. Brushing too hard can also damage your gums and teeth in the long run.

Goosebumps are a state of the skin caused by cold, fear, or excitement.

When a person has goosebumps, small bumps appear on the skin and cause hair on the arms to stand erect. This is due to a contraction of miniature muscles attached to each hair. Each muscle causes a shallow depression on the skin surface which causes the surrounding area to protrude.

Wisdom teeth have no purpose.

Wisdom teeth are vestigial third molars that have helped in grinding plant tissue. Researchers believed that the jaws of human ancestors had larger jaws with more teeth. Often wisdom teeth are removed to prevent complicated problems that could occur if it continues to grow inside the mouth.

Scientists have yet to figure out why we yawn.

Although some studies suggest that we yawn to cool our brains down and keep the brain from clotting. Another reason suggests that it could be the body’s way of waking itself up. The motion from yawning also helps stretch the lungs and their tissues and allows the body to flex its joints and muscles.

Humans are the only beings on earth that have chins.

Even our close primate ancestors such as chimps do not have chins. Research has hypothesized that we developed the modern human chin to aid the jaw in tasks such as chewing.

Most of the air you breathe goes out from your nostrils.

This is good because this is how our bodies naturally breathe. Breathing through our nose allows us to take fuller and deeper breaths. It provides the lungs greater amounts of oxygen to distribute through the body. The nose also has hair inside that helps filter the air we breathe.

The human body experiences rigor mortis after dying.

Have you ever wondered what happens to the human body after death? Human bodies experience a condition known as rigor mortis after death, where muscles in the body become rigid. This process usually starts 3 to 4 hours after death, and lasts up to 36 hours.

The human nose is capable of detecting over 1 trillion smells.

The human nose contains around 400 types of scent receptors that can detect odors. These receptors are capable of detecting at least 1 trillion different odors. However, human beings are only able to differentiate about 10,000 odors from each other.

A human being can live with only one kidney.

A person may have one kidney removed to treat an injury or disease. Even with one kidney, they may still be able to lead normal and healthy lifestyles. Some people are also born with only one working kidney.

When you crack your knuckles, it isn’t your bones that make the sounds.

The cracking sound is mainly due to the tiny bubbles that formed from the fluids of the joint. As the pressure changes, these bubbles pop, thus creating a cracking sound. In earlier days, people believed that cracking your knuckles could cause arthritis. However, modern research has shown that there is no direct correlation between the two.

Eight different interwoven muscles make up the tongue.

These muscles are similar to an elephant’s trunk or even an octopus’ tentacle. Covered in a mucous membrane, they can move in any direction. This mucus keeps the tongue moist which helps us detect tastes.

All human beings are 99% identical.

The genetic we have are almost completely identical to one another. The remaining 1% plays a big factor in giving researchers clues about the causes of diseases and other illnesses. However, no two humans are 100% genetically identical.

A surgical procedure that removes fear from your brain exists.

Selective amygdalohippocampectomy can treat patients with epilepsy. While this may sound like a process you would want to try, it comes with consequences. Some side effects of this surgery include impaired memory and certain defects in visual perception.

The pineal gland got its name from its shape.

The pineal gland closely resembles a pine nut. This gland secretes melatonin into our brain. Melatonin is a serotonin-derived hormone that helps modulates sleep patterns.

Our hair grows incredibly fast.

The hair on our scalps can grow a length of 6 inches a year. Our hair grows about half an inch per month on average. Hair grows only a little bit slower compared to the bone marrow in our bodies.

No one understands why we have fingerprints.

Most scientists believe that the purpose of fingerprints is to help us better grip objects. However, it was later discovered that this was not the case at all. More today, fingerprints can identify a person because no two prints are alike.

Blushing is due to a reaction of the sympathetic nervous system.

This system is a part of our “fight or flight” response. Blushing happens when the adrenaline gets released and speeds up your heart rate. This causes your blood vessels to dilate to improve your blood flow and oxygen delivery.

Your brain is active even when you are asleep.

As an adult passes into deeper stages of sleep, brain waves begin to slow down and become bigger. As your sleep deepens, the brain activity moves into REM sleep. The muscles then relax and breathing is regulated to help the body recover from the long day.

Your left lung is not as big as the right lung.

The reason why is so that the right lung can make room for the liver. The left lung is narrower because it needs to make room for the heart. Another difference between the two lungs is that the left has two lobes, while the right has three.

The human teeth are as strong as a shark’s teeth.

Scientists have found that human teeth are just as strong as the teeth of sharks. This is even though human teeth are from a softer mineral compared to the ones found in a shark’s. The white enamel found on your teeth is even stronger than bone.

Our brains have a memory capacity.

Approximately, this capacity is equivalent to around 4 terabytes of memory. Short-term memory is capable of holding only an average of 7 items. The brain makes use of neurons to remember memories. These sometimes combine with similar memories that move to long-term memory.

The human embryo develops fingerprints within 3 months of conception.

This is roughly estimated to occur during a woman’s 23rd week of pregnancy. Ridges also begin to form in the palms of the hands and the soles of the feet. These fingerprints have three distinctive features: arches, loops, and whorls.

A person will forget their dreams 90% of the time.

This is due to the neurochemical conditions that the brain is in during REM sleep. This phase is a state where rapid eye movements and dreaming occurs. A theory suggests that dreaming occurs when the brain processes information and eliminates unnecessary information.

A child can ask over a hundred questions a day.

Certain studies have found that the average 4-year-old will ask more than 400 questions a day. Meanwhile, a child will ask an average of 40,000 questions between the ages of 2 to 5 years. Kids ask several questions a day to further expand their knowledge.

You can lose weight from the smell of bananas.

A study found that overweight people who smell green apples and bananas when feeling hungry lose more weight than those who don’t. Smelling a natural sweet smell can curb hunger. By using this method, these people can lose weight faster.

Human lips are very sensitive.

They are sensitive because they have the thinnest layer of skin on the body. The lips have over 1 million nerve endings. Lips also never sweat because they lack sweat glands.

A person will always be taller in the morning than in the evening.

We become taller in the morning because the cartilage on our knees decompresses during sleep. Throughout the day, the cartilage in our knees slowly compresses due to the weight of our bodies and the pull of gravity. On average, we are about 8 millimeters taller in the morning.