Fun Questions | What is the uneven structure above the mouth?

What is the uneven structure above the mouth?

Palatal fold model | Image source: Patil, MS, Patil, SB, & Acharya, AB (2008)

Lick the front part of the upper part of your mouth. Can you feel some kind of uneven structure? Chew a piece of gum, print it there, and then spit it out. You can clearly see a series of horizontal curved folds, just like the lines on the sole of a shoe. This structure is called palatine rugae, and "palatine" refers to the upper wall of the mouth.

Source: Dos Santos, KC, Fernandes, CMS, & da Costa Serra, M. (2011)

The palatal folds are formed at 12 to 14 weeks of fetal development, and then accompany us throughout our lives until we die. Everyone's palatal folds are unique, just like fingerprints. During orthodontic treatment, the position of the teeth will change greatly, but the palatal folds still retain their main characteristics, which doctors and researchers can use as a mark.

Model with palatal folds labeled | Image credit: Sivaraj, A. (2013)

In the field of forensic identification, palatal folds can also be used as auxiliary identification evidence, especially when there is a lack of facial and fingerprint clues. In the case of full-face third-degree burns, their facial features have been blurred, but 93% of the injured have intact palatal folds.

Palatal folds are also closely related to congenital malformations such as cleft palate. Researchers have found that the palatal folds of most cleft palate patients show certain pattern characteristics, so they can be used for screening.

Some linguists believe that palatal folds are also important for accurate pronunciation. Certain sounds require the tongue and palate to be in a specific relative position, and missing or abnormal palatal folds may cause certain sounds to be pronounced incorrectly.

Look around, there may be other hidden marks on your body.

Why can miracle fruit turn sour taste sweet?

Miracle fruit | Source: Wikipedia

Miracle fruit is native to tropical areas of West Africa and belongs to the Sapotaceae family. The amazing thing is that this fruit itself has no sweetness, but it can make sour things sweet, even lemons can turn into candies.

The secret of the miracle fruit's "control" of taste lies in the miracle fruit protein (miraculin) it contains. This is a glycoprotein, with sugar in its name but not sweet. Its power lies in its ability to "blind" taste buds. However, its effect is limited by the pH value of the environment. In a neutral environment, miracle fruit protein can bind to taste receptors, but will not activate sweet receptors. At this time, when you eat sweet things, it will not make you feel sweeter. But in an acidic environment, such as eating a lemon, miracle fruit protein will activate sweet receptors, thereby highlighting the sweetness, and the more sour the environment, the stronger the sweetness perception.

In other words, miracle fruit doesn’t come out of nothing, it just changes your taste buds, making the natural sweetness of the fruit more prominent. Even lemons contain a lot of sugar.

However, the miracle fruit cannot always "cheat" the taste buds. Under the repeated flushing of saliva, it basically loses its effect after half an hour. But at least it allows you to taste a hint of sweetness that has been buried in the sourness.

Why do you walk quietly down the corridor?

Some automatic sensors will also light up?

Image source: Pixabay

Many corridors are equipped with automatic sensor lights, which light up silently when someone passes by at night. Obviously, there is no enthusiastic uncle monitoring the corridor in the basement, but technology is illuminating life.

A common sensor light is the voice-activated sensor light. This sensor light is equipped with a vibration-sensitive voice-activated element. If the person passing by makes enough noise, the voice-activated element will receive the vibration caused by the sound wave and connect the circuit. When the voice-activated element is not sensitive, we even have to stomp our feet hard to make the light turn on.

However, in some new buildings, the automatic sensor lights seem to be extremely sensitive. Even if we deliberately don't make any noise, the lights will light up as we pass by. This kind of light is probably not a voice-activated light, but an infrared sensor light.

The human body is a stable heat source that radiates infrared rays continuously. At a constant body temperature, the 10-micron wavelength infrared rays emitted by the human body are the strongest.

Human body photographed by infrared detector

The infrared sensing lamp is equipped with a human infrared sensing module. The core of the module is a pyroelectric infrared sensor, which can detect infrared rays with a wavelength of about 10 microns. This temperature change will trigger the pyroelectric effect, converting thermal energy into electrical energy and making the circuit conductive.

However, in the daytime when there is plenty of light, the well-lit corridor does not need the induction lamp to work. In order to save energy, these induction lamps are generally equipped with photoresistors, whose resistance changes with the light intensity, and the induction lamps only work when the surrounding light is weak.

It is said that turtles have a long lifespan.

Why do pet turtles bought on the market not live long?

Red-eared slider | Source: Wikipedia

From ancient times to the present, turtles have been a symbol of longevity, at least they live longer than humans. However, pet turtles often die before they can see their owners to the end of their lives.

Excluding the factors of buying sick turtles or the owners not raising them well, the lifespan of ordinary pet turtles is actually not as long as we think. Most pet turtles on the market are "red-eared sliders", scientifically known as red-eared sliders (Trachemys scripta elegans), named for the red textures on both sides of their heads. The so-called "red-eared sliders" are not actually from Brazil, but originally lived in the Mississippi River and the Grande River in the United States and Mexico. The real red-eared slider is the South American painted turtle (Trachemys dorbigni), which was later replaced by the red-eared slider due to transportation costs. The latter has now spread all over the world and has even become an invasive species (don't release it into the wild at will!).

The life span of red-eared sliders is far less than that of humans. Like most freshwater turtles, they only live 20 to 30 years, with a few living over 40 years. In captivity, their life span is often even shorter.

Although the red-eared slider does not deserve the title of centenarian, there are still many centenarians in the turtle family, but none of them are as exaggerated as the "thousand-year-old turtle".

Tortoises can live up to 50 years, sea turtles can live over 70 years, and tortoises can live between 80 and 150 years. Some, such as the Galapagos tortoise, can live over 150 years.

Jonathan, the oldest turtle | Source: Wikipedia

The oldest living land animal is an Aldabra tortoise named Jonathan, who was born in Seychelles in 1832 and is now 189 years old. However, most of these long-lived tortoises are threatened.

Turtle: HP 100+

Meet a two-legged beast: Health bar -100

Bringing science home

Written by | Mirror

Cover image source: Wikimedia Commons

References:

https://docs.qq.com/doc/DRlZRR0pxRHpXRmlh