Here are five common notions about the human body and whether they are true or not:

1) You can smell while you are asleep: False

The olfactory system shuts down when you go into the REM cycle in sleep, which means smells cannot give the human body a reaction while sleeping.

2) Your stomach lining blushes when you do: True

The human body releases adrenaline when someone gets embarrassed, and this causes the blood vessels in the body to dilate, causing them to blush. Since the blood vessels in the stomach are close to the surface, much like the human face, the stomach lining also blushes when the adrenaline is released and the blood vessels dilate.

3) Your fingernails and toenails grow at the same speed: False

The human toenail grows at a slower pace than the human fingernail. This is because of the evolutionary connection between the terminal phalanges (the outer bone in the toes and fingers) and the pace of nail growth, causing the tips of toes to grow slower than the tips of fingernails.

4) The human liver can regenerate itself with only half of its tissue mass: False

It only takes a quarter of the human liver’s mass to completely regenerate itself. This means it only takes one fourth of a liver for failed liver make itself healthy again.

5) Each human tongue has its own unique print: True

All humans all have a unique tongue print, just like fingers. The tongue has its own geometric and physiological texture information. This means that the human tongue print can possibly be used to identify individuals. For more information about this topic, click here.