[Source: Xianyang Science and Technology Association_Popular Science Xianyang]
It is difficult for most people to get up every morning, but sometimes, you When you are sleeping soundly on the bed, a “third party” will suddenly appear to wake you up immediately, then throw away the hot quilt and get out of bed to go to the toilet.
Yes, this “third party” is urine (you and I said that the Poop wakes up, sorry, we can’t be friends), let’s talk about it today.
First, let’s see how urine comes from?
Urine is produced by the human body’s urinary system.
When we drink water, the body will use most of it, leaving a small amount of excess The water and useless substances in the blood will come to the kidneys, (after being reabsorbed by the renal tubules) to form urine here, but they will not be stored in the kidneys, because there is no space for garbage here.
Just like the garbage disposal site in life, there is also a temporary garbage in the human body Disposal site, after the urine is formed in the kidney, it comes to this “temporary garbage disposal site” – the bladder along with the ureter.
The bladder is a bit like a more elastic ball, with the continuous injection of urine , its volume will continue to increase, and this is the last barrier for urine in the human body to “release itself”.
The bladder is mainly composed of three structures, namely the serosa layer of the outer wall, the muscle The mucosal layer of the lining and the inner wall also has a urothelial barrier to prevent infection on the surface of the mucosal layer.
In the smooth muscle fibers of the muscle layer, there lives a guard “garbage disposal site”. “Guardian – the detrusor muscle, which controls the discharge of urine.
The storage capacity of human bladder is about 300~500ML, when the amount of urine At this time, the stretch receptors in the bladder will send a signal to the parasympathetic nervous system: “Go and tell the detrusor, the bladder is almost full!” The urge to urinate occurs.
Then the detrusor muscle receives the signal (muscarinic receptor), non-stop, the detrusor muscle hurries through the fast channel – ordinary visceral afferent fibers to the central nervous system Report the situation.
After the central nervous system gave the instruction of “OK, urinate”, expel urine The muscles begin to contract, the sphincter that compresses the urethra relaxes, and the urine finally “pours out” from the bladder.
Although I said a lot, the process is actually completed in a few seconds .
Know the formation and excretion of urine, so how did we wake up from the urine in our sleep?
This has to start from childhood, because the baby’s central nervous system is immature, and the capacity of the bladder is only 1/10 of that of an adult, and the muscle contraction strength is not strong. Therefore, when the baby’s bladder senses that the urine reaches a certain amount, it will “open the gate and release the water” by itself, which is not controlled by the brain at all.
With the growth of age, all aspects begin to mature. For peeing, you will no longer want to pee, but will pass The brain’s judgment, autonomously chooses the time and place to pee.
Because of this, during sleep, when the excess waste produced by metabolism in the body’s blood forms urine, the bladder will start to continuously send “request to pee,” to the brain. Can’t stand it” signal! !
But the brain will evaluate the signal strength by itself. Generally, the signal of 100~200ml will not take care of it. Only when the amount in the bladder has to be released, the brain will call. You get up to pee so you don’t burst your bladder.
Interact, do you think the bladder will burst with urine?
In history, the famous 16th-century astronomer Tycho Brahe burst his bladder because he held back his urine. After chemical analysis of He’s body, the cause of his death was further determined.
It is said that at a royal banquet, Tycho didn’t want to lose his party and left halfway, so he resisted the strong urge to urinate, but unexpectedly, the banquet time It is relatively long, obviously, the small bladder can’t bear the menacing urine, and eventually leads to the rupture of the bladder…
Editor in charge: Popular Science China
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