Why is the mouth of a mosquito not very hard, but it can pierce into a person s skin?

Whenever we enter the hot summer, I believe that you will have all kinds of troubles when you fight, such as many times when we go out, because we are worried about being tanned, we will do all kinds of necessary sunscreen measures, and there will be a lot of sweat every day, and finally there are a lot of mosquitoes, we all have such questionsWhy is the mouth of a mosquito not very hard, but it can pierce a person's **? In fact, this has a lot to do with the pressure in our air, so let's analyze it in detail.

Whenever we enter the hot summer, many of us will have such troubles, no matter where we go, those mosquitoes are particularly numerous, such as mosquitoes on the dining table, blood-sucking mosquitoes and small mosquitoes, all kinds of mosquitoes fly around in the air, seriously affecting our normal life, not to mention which mosquitoes will suck blood, it is generally easy to appear at night, if you don't light mosquito coils or spray some insecticides and the like, it is difficult to fall asleep at night, which will also seriously affect our sleep quality.

We all know that the mouth of the mosquito is not very hard, but it can pierce into the human body, because the mouth of the mosquito is not very hard, so if they want to pierce the human body, then they can only work the mouth, at this time they will increase the strength of the mouth piercing, and the mouth of the mosquito is particularly sharp, especially the kind of sharp-billed mosquito, the area is very small when it pierces the **, so small that you can hardly see it.

In the process of piercing in, a force called strong pressure will be generated, and it is because of this force that the mosquito will pierce into the human body. In addition, there are a lot of pores in our human body, and sometimes we don't notice it, so it is quite easy for mosquitoes to pierce the human body. After we are bitten by a mosquito, a lump will grow on the bite site, which is very itchy, so we need to take necessary measures to prevent insects.

Because there are pores in people's **. Moreover, the mouth of the mosquito is relatively thin and soft, and it is easier to penetrate into the pores of the human body, so as to absorb the blood of the human body, which is a means of survival.

The mosquito's mouth is very thin, and it has six needles, and the mouth needles are serrate, which can be easily cut**, the mouthparts are inserted into the **, and then anticoagulants are injected to prevent blood clotting.

According to the pressure calculation formula: p = f s. The magnitude of the pressure (i.e., the degree to which the mosquito penetrates **) is equal to the force used by the mosquito penetrating divided by the contact area between the mosquito's mouthparts and **.

In the case of constant force, the smaller the area, the greater the pressure (inversely proportional). It is well known that the contact area is small, so the pressure is high, and the mouthparts of the mosquito can penetrate**. Also, ours is not an iron wall, it also has pores.

The human ** is still quite elastic, but the mosquito's mouth is so small, how can it pierce into the human ** to suck blood? I'm going to dissect the mouth of a mosquito.

The most annoying and disgusting creature in the world is probably mosquitoes, and if mosquitoes fly when sleeping at night, it can make people feel collapsedAnd it will also suck blood, and people will wonder why the mosquito's mouth is not very hard, but it can pierce people's **? This is mainly because there is a barb under the mouth of the mosquito, which can harm our **.

First of all, in fact, if we compare the creatures in nature, it is really more fragile, after all, it is soft, and for creatures like mosquitoes, they prefer to suck blood, especially at night, stay in the wild for a night, and the next day get up the body is full of bags, which is to be sucked by mosquitoes and bite, etc., and after the discovery of biologists, the mosquito itself is not hard, but there is a barb under the mouth, which can instantly improve the ability to pierce, The sting is so small that it's almost invisible, but those who have learned about pressure must know that although the surface area is small, the corresponding pressure will be higher.

For example, in ordinary life, a pair of scissors can be good for the area pressure, but it takes a certain amount of strength to pierce some objects, but if it is just a small needle, although it is small, the area that can be contacted is also very fast, but the targeted pressure that can be brought is very large, so it can achieve a good effect, and the same is true for the barbs under the mosquito's mouth.

Especially for summer, many times do not pay attention to closing the windows at night, a lot of mosquitoes will fly in, and the next day I get up only to find that I have some more bags on my body, so it is recommended to light a mosquito coil and close the window before going to bed at night, which can reduce the number of mosquitoes well, and usually pay attention to the hygiene of the house, after all, mosquitoes prefer places with a bad environment, and there are many viruses themselves.

Mosquitoes can't open their mouths, so they won't take a bite on it, it's actually a worm that has already stabbed into people with 6 needle-like structures, and these short needles are the center of mosquitoes' mouthparts.

These short needles suck human blood in the same way that they draw blood; The mosquito also releases saliva containing anticoagulants to prevent blood from clotting, so that it can feast peacefully. When the mosquitoes are full of food and drink, and float away, all they leave behind is an itchy swollen bag.

However, the itchy sensation is not caused by a short needle pricking or chemicals in the saliva. We feel itchy because the body's immune system releases a protein called histamine to fight foreign substances, and this immune response triggers an allergic reaction at the bite site. Histamine causes swelling of the tissues around the bite when blood flows to the bite site to speed up tissue recovery, and the intensity of this allergic reaction varies from person to person, with some people having a more severe allergic reaction to a mosquito bite.

Let's first study the two most critical parts of the mosquito mouth needle penetration**: the upper lip and the lower jaw. The tip of the upper lip is very pointed, with a radius of curvature of about 100 200 nanometers, which is much smaller than the grain size of conventional metal materials (e.g. 1 100 microns for industrial pure iron), and such a small "needle tip" is difficult to make with ordinary metal materials (the radius of curvature of the tip of an ordinary sewing needle is about 100 microns).

The tip of the jaw of mosquitoes is also very sharp, with a radius of curvature of about a few hundred nanometers. Interestingly, it has a row of tiny and delicate serrated structures on both the outside and inside of its jaw (see figure), which have sharper tips and a radius of curvature of about 50 150 microns. In general, the number of serrations at the tip of the jaw varies depending on the species of mosquito.

Mosquitoes with fewer than 14 serrations feed mainly on human blood, while those with a higher number of serrations feed mainly on the blood of domestic animals. The greater the number of micro-nano sawtooth, the stronger the piercing ability.

We measured the mechanical properties of the upper lip and lower jaw of mosquitoes using nanoindentation technology, and found that the elastic modulus is comparable to that of polymer materials, and the surface hardness is comparable to that of metal materials, and the closer to the tip the surface hardness is, the higher the surface hardness. It is this mechanical property that makes the mosquito mouth needle not only easy to pierce**, but also freely bend under the skin to find capillaries.

Observed with a high-speed camera, it was found that the process of mosquito mouth needle piercing** was not a simple puncture.

Before piercing, the mosquito will straighten its mouthparts and stab at ** quickly. It is a dynamic impact process: the tip of the upper lip first punctures the ** surface, after which, as the penetration depth increases, accompanied by periodic vibrations, which drives the lower jaw with micro-nano serrations to be sawed open**.

In the initial stage of vibration penetration, the head of the mosquito vibrates at a high frequency, about 10 15 Hz; In the intermediate penetration phase, the vibrational frequency gradually decreases to 6 8 Hz; The vibration frequency in the final stage is only about 3 5 Hz.