If you vote for one of the most annoying insects, many people will probably vote for mosquitoes.
This annoying little insect can cause harm to humans, both physically and psychologically. Physiologically, mosquitoes sucking blood will leave a strange itchy bag, which can be upsetting. On the psychological level, it is really uncomfortable that humans, creatures at the top of the food chain, can be such small prey. In fact, the harm of mosquitoes is not limited to this, it may also become a vector for disease transmission in the process of sucking blood, bringing greater harm to humans. So are there any other potential hazards that mosquitoes can be doing besides spreading diseases?
If a mosquito accidentally pierces a large artery in the human body while sucking blood, is there a possibility of causing massive bleeding?
Compared with the size of the mosquito, the "needle" it uses to suck blood is indeed quite long, accounting for about half of the mosquito's body length. However, the size of the average mosquito is 3 to 6 mm, so the length of the mosquito's mouthparts is about 2 mm. Can a 2mm mouthpiece pierce a human **? It's really okay, because the human epidermis is relatively thin, the thinnest part is on the eyelids, and the epidermal layer here is only 004 mm or so, which is why mosquitoes always like to bite on the eyelids, which are the easiest to puncture.
The thickest part of the human epidermis is the heel, where the thickness of the epidermis can reach 1It's about 6 mm, so mosquitoes hardly visit here.
Human ** is composed of three parts: epidermis, dermis and subcutaneous tissue, when the mosquito punctures the epidermis with mouthparts, it comes to the dermis, which is the main area where mosquitoes suck blood, because there are a large number of capillaries in the dermis, mosquitoes will use their mouthparts here to repeatedly pluck to find capillaries, if not found, they will give a second needle. It can be seen that mosquitoes do not need to completely puncture the human **, only need to puncture the epidermal layer, and they can achieve their own purpose of sucking blood.
Are mosquitoes sure they can't reach the arteries of the human body? Neither is it.
The arteries of the human body are also divided into many kinds, in the terminal branch of the brachial artery, there is a smaller artery, called the "radial artery", in comparison, the radial artery is the closest to the human body, the deeper one is about 5 to 10 mm, and the shallowest radial artery is only 2 to 3 mm away. It can be seen that if the mosquito tries its best, it can still barely touch the radial artery, but being able to touch it does not mean that it can suck blood from the radial artery. We know that mosquitoes have very thin mouthparts, when in fact their mouthparts are even thinner than we know.
From a macro perspective, it seems that mosquitoes have only one blood-sucking needle, but in fact this is not one, but six.
The two outermost needles used by mosquitoes piercing **, while the two sublateral needles are responsible for opening ** tissues and looking for capillaries. Once the blood vessels have been found, the mosquito inserts two central needles into the capillaries, one injecting anticoagulant compounds and the other sucking blood. So even if a mosquito can barely reach the radial artery, such a thin mouthpart cannot puncture the radial artery. Why? Because the radial artery is not like a capillary, it is protected by the arterial wall.
The arterial wall can be divided into three layers, from the outside to the inside: the adventitia, the medial and the endovascular intima, of which the vascular metrium is the thickest, which is composed of elastic membrane and smooth muscle.
Not to mention the thin mouthparts of mosquitoes, even if you let humans bite with their teeth, it is difficult to bite them, if you don't believe it, you can take a piece of raw yellow throat that has not been boiled in soup and try it. Why are arterial walls so strong? The reason is actually very simple, because the blood pressure in the human arteries is very high, and if there is no strong arterial wall to protect it, the consequences can be imagined. From this, we can also imagine that even if a mosquito is allowed to insert its mouthparts into a human artery, it will not be able to suck blood, and its strong blood pressure will not be able to cope with it.