"You, what do you mean......"

Liang Yujian was a little weak, and suddenly a bad premonition rose in his heart, and he hurriedly thought about what he just said. Pen, fun, and www.biquge.info

That's right, the neurons in the brain really can't tolerate ischemia and hypoxia!

The ability of brain cells to tolerate it is indeed three or four minutes at most!

Brother Deng does look stupid now!

That's right!

Liang Yujian seemed to have regained his confidence, his chest straightened, and then he was defeated the moment he saw Yang Tian's eyes.

Yang Tian looked more confident than himself......

"Yes, you're right, brain cells do have poor tolerance to ischemia and hypoxia, instantaneous ischemia and hypoxia, such as squatting for a long time and standing up from the ground for a long time, can cause dizziness, and long-term ischemia and hypoxia can indeed lead to irreversible damage to the brain."

Yang Tian first affirmed Liang Yujian's previous statement, and then silently glanced at Liang Yujian, who suddenly became excited, "But there is a premise for you to say so much, that is, the local blood supply is insufficient." ”

Liang Yujian's expression froze on the spot again, and the bad premonition in his heart became stronger and stronger.

This time, it became Yang Tian who talked eloquently, "Sometimes things don't really go for granted as you think, human beings can live to this day and have gone through so long of evolution, how can they make such a low-level mistake in evolution?" ”

"Biology textbooks in middle and high school will tell you that arteries and veins can be connected through a network of capillaries, and arterial blood is exchanged with body fluids in the capillaries to become venous blood."

Yang Tian glanced at everyone, especially the little fat boss and the fourth, and then continued:

"But in fact, arteries and veins are sometimes directly connected by vascular branches, forming small arteries and veins, which can be seen in many parts of the body such as fingertips, lips, nose, external ear skin, genital erectile tissue, etc., which can shorten the circulatory pathway and regulate local blood flow and body temperature."

"In addition, in fact, arteries and arteries, veins and veins can also be connected to each other with the help of vascular branches or anastomosis branches, which we call vascular anastomosis."

"The artery that does not anastomosis with the adjacent artery is called the terminal artery, and this kind of artery is really a large piece of death if there is a problem, for example, the retinal terminal artery is a typical terminal artery, if it is blocked, it will directly lead to ischemia or even necrosis of the retinal part of the tissue."

Yang Tian paused, took a breath and continued.

"It is true that as you said, the large blood vessels of the human body often have one on the left and one on the left, but many parts of the human body and the two arterial trunks of the organs actually have anastomosis, in addition, the parts that are easily compressed or often moved will have an arterial network formed by multiple arterial branches, such as the arterial network of joints such as the elbow."

Hearing this, the little fat man involuntarily touched his elbow, his eyes also glanced up at his elbow, and finally sighed deeply after looking at it for a long time.

I'm so fat, all I see is white meat, I can't even see the veins, and I say arteries......

It is said that medical students will make full use of their bodies when they learn anatomy, what blood vessels, joints, adjacent positions or something, if you get the test, you can touch your body directly, the little fat man thinks that this Nima can only be done by emaciated medical students, and it is better not to touch it......

Over there, Yang Tian continued to popularize science with everyone, "And the brain, as a vital organ in the human body, think about it, is it possible that it does not have this kind of arterial anastomosis?" ”

"No way."

Everyone shook their heads in a daze.

What Yang Tian said is very reasonable, even the elbow has an arterial anastomosis because of frequent activity, so the brain is so important that there must be a plan, just like there must be a plan before a major action, B.

Liang Yujian was a little embarrassed, he seemed to be really taking it for granted, and was about to say something to make up for it, when his mouth opened, and Yang Tian began to talk again.

"The cerebral artery ring, also known as the Willis ring, is a ring structure at the base of the brain surrounded by nine blood vessels, including the beginning of the anterior cerebral artery on both sides, the posterior cerebral artery on both sides, an anterior communication branch, two posterior communication branches, and the ends of the two internal carotid arteries that I just held down."

Yang Tian silently glanced at Liang Yujian, "Under normal circumstances, the blood on both sides of the cerebral arterial ring will flow separately and will not mix with each other, but once a critical situation occurs, it can redistribute and compensate the blood under certain circumstances." ”

"And I just held down the common carotid artery on the right side of this brother, although it obstructs the blood flow of the two branches of the common carotid artery, the internal carotid artery and the external carotid artery, but because of the presence of the Willis ring, it does not affect the blood supply to the brain."

"What's more, it was only two minutes and sixteen seconds and 35 seconds from the time I pressed my thumb to the time I released it, and the human body was still able to cope with this situation on its own."

In fact, he has practiced similar situations in the systematic teaching space, and with accurate timing, he is still completely sure.

"If it really caused a lack of oxygen to the brain, this brother wouldn't be so sober now, and he would do whatever I wanted, and he should have fallen directly to the ground at this time."

Yang Tian faced Liang Yujian, "I said this, do you understand?" ”

"Ming, I understand......"

Liang Yujian smiled with an embarrassed face, but was slightly annoyed.

When he talked about vascular anastomosis just now, he already knew that he was wrong, was it necessary to hold on to it so stubbornly? Forcibly popularizing science or something, isn't it interesting!

Although Yang Tian seemed to understand a lot of things after explaining it like this, his face hurt! It hurts so hot! Could it be because he and Deng Chaoyang blew too much before, and Yang Tian took the opportunity to retaliate?

Liang Yujian gritted his teeth and felt extremely painful, he didn't know that Yang Tian had a system, and he didn't know that Yang Tian had a series of tasks for popular science......

Brother Deng leaned forward in a trance, faithfully carrying out Yang Tian's orders; Zhang Meng, a girl in a wow-clothed shirt, has completely hidden outside; Liu Yang's face was a little sneering, and he felt a little sore when he looked at Liang Yujian, who was full of pain.

Li Yan, who was dressed in a campus style, looked at Yang Tian with a somewhat complicated gaze at the moment, Yang Tian's slap in the face and let Liang Yu build a foreign appearance can certainly make him lose points in front of Han Bing, and then he will have the opportunity to take advantage of the situation, but at the same time, he witnessed Liang Yujian building a foreign appearance, will this make him feel guilty?

In contrast, the little fat boss and the fourth are much more relaxed, although they didn't laugh, but the rise in the corners of their mouths was visible to everyone, and even Han Bing had a trace of emotion on his face.

Of course, Xie Xin was the happiest person who laughed, giggling without caring about Liang Yujian's feelings.

Liang Yujian's face was blue and white for a while, his lips were trembling, and the green tendons on his neck were suffocated, and he didn't dare to scold.

The Nima family is a good sister of the goddess, and they are also good sisters holding hands, and they can't afford to offend themselves!

Xie Xin laughed for a long time and finally laughed enough, and he also felt that he was a little too much, thinking about whether he should do something to make up for it, otherwise Liang Yujian would be too embarrassed.

So she remembered the question that Liang Yujian asked just now but Yang Tian didn't answer, "Yang Tian, since people haven't become stupid now and the nosebleed has stopped, why do you still call an ambulance?" ”

As soon as he heard Xie Xin ask, Liang Yujian nodded hurriedly, and at the same time felt a burst of gratitude in his heart, it was still this girl who gave face.

Then Yang Tian smiled, "Yes, I was about to say this." ”