20 Surprising Unknown Facts about Human Body

The human body is a biological marvel, with extraordinary capabilities and intricacies that mostly go unnoticed in the flow of life. Much about our anatomy and physiology has been well documented; however, there are a number of curious aspects that rarely reach the spotlight. From hidden capabilities to weird biological happenings, these little-known facts reveal just how amazing our bodies are.

1. Your heart beats over 3 billion times in a lifetime.
   The average human heart beats about 100,000 times in one day; thus, calculating over a life span of 80 years, it beats over 3 billion times.  
2. Your stomach lines itself anew every 3 to 4 days.
   To avoid self-digestion by its own acid, your stomach replaces its entire mucosal lining every few days.  
3. Humans glow in the dark (sort of).
   Our bodies emit a very dim, invisible light called bioluminescence to the most sensitive instruments, strongest in the mouth and nose, but a thousand times too weak to be seen by the human eye.
4. Your brain has more connections than the Milky Way has stars.
   With about 86 billion neurons, the brain forms over 100 trillion synaptic connections—that is way over the number of stars in our galaxy.
5. Bones are five times stronger than steel.
   Human bones can take and support huge amounts of pressure and strength, and therefore, human bones are five times as strong as steel with the same given mass.
6. You have unique tongue prints.
   Like fingerprints, your tongue has a singular set of ridges and patterns, structurally making it an identifier.  
7. Your body can survive without a great part of the organs.
   Humans can function with one kidney, one lung, and as much as 75% of the liver removed.
8. The human body has about 37.2 trillion cells.
   Each cell is ceaselessly working for the maintenance of homeostasis to keep one alive.
9. Your cornea has no supply of blood.
   It is that part of the body that gets its oxygen directly from the air and not from blood.
10. Your skin replaces itself every 28 days.
    Up to 30,000-40,000 dead skin cells are discarded every minute and constitute the major portion of household dust.  
11. The liver performs over 500 functions.
    From detoxification of chemicals to the synthesis of bile, the liver is an indispensable part of more than 500 biological processes.  
12. Your nose can detect over a trillion different scents.
    With an estimated 400 scent receptors, the olfactory system is more sophisticated than previously thought.
13. The small intestine is about four times as long as your height.
    Being about 22 feet in length, it's folded tightly to fit within the abdomen.
14. Babies have more bones than adults.
    At birth, one has about 300 bones; many of them merge during growth, leaving the adult with 206 bones.
15. There is a spare brain in your belly.
    The gut, or more correctly the enteric nervous system, contains over 100 million neurons and can act independently of the brain.
16. The average human produces enough saliva to fill two swimming pools.
    In a lifetime, your salivary glands produce as much as 25,000 quarts of saliva.
17. Your hair contains traces of gold.
    Human hair contains small amounts of the precious metal, along with other trace elements.
18. You lose about 1% of your body water every hour through the process of respiration and sweating.
    The body continuously loses water through respiration and to maintain the normal temperature, thus keeping all organs functional.
19. Your body can make its own antibiotics.
    The proteins in your skin and mucus, including defensins, serve as natural antibiotics to curb infection.
20. Your ears never stop growing.
    Unlike most body parts, ears and noses grow larger as we age due to gravity and cartilage expansion.

The human body is a remarkable biological machine, filled with wonders that extend far beyond what meets the eye. These lesser-known facts provide insight into the astonishing capacity, versatility, and strength of our anatomy and physiology. From its microscopic cells to its macroscopic functions, the body ceaselessly amazes scientists and fills all who take the time to explore its mysteries with wonder. Indeed, knowledge about the human body increases our appreciation for the miracle of life itself.