Placeholder Image

Subtitles section Play video

  • It begins with a bit of discomfort

  • and soon becomes a pressing sensation that's impossible to ignore.

  • Finally, it's all you can think about, and out of sheer desperation, you go on a hunt for a bathroom until "ahh."

  • Humans should urinate at least four to six times a day,

  • but occasionally, the pressures of modern life forces us to clench and hold it in.

  • How bad is this habit, and how long can our bodies withstand it?

  • The answers lie in the workings of the bladder,

  • and oval pouch that sits inside the pelvis.

  • Surrounding this structure are several other organs

  • that together make up the whole urinary system.

  • Two kidneys,

  • two ureters,

  • two urethral sphincters,

  • and a urethra.

  • Constantly trickling down from the kidneys is the yellowish liquid known as urine.

  • The kidneys make urine from a mix of water and the body's waste products,

  • funneling the unwanted fluid into two muscular tubes called ureters.

  • These carry it downward into the hollow organ known as the bladder.

  • This organ's muscular wall is made of tissue called detrusor muscle

  • which relaxes as the bladder fills allowing it to inflate like a balloon.

  • As the bladder gets full, the detrusor contracts.

  • The internal urethral sphincter automatically and involuntarily opens,

  • and the urine is released.

  • Whooshing downwards, the fluid enters the urethra

  • and stops short at the external urethral sphincter.

  • This works like a tap.

  • When you want to delay urinating, you keep the sphincter closed.

  • When you want to release it, you can voluntarily open the flood gates.

  • But how do you sense your bladder's fullness

  • so you know when to pee?

  • Inside the layers of detrusor muscles are millions of stretch receptors

  • that get triggered as the bladder fills.

  • They send signals along your nerves to the sacral region in your spinal cord.

  • A reflex signal travels back to your bladder,

  • making the detrusor muscle contract slightly,

  • and increasing the bladder's pressure so you're aware that it's filling up.

  • Simultaneously, the internal urethral sphincter opens.

  • This is called the micturition reflex.

  • The brain can counter it if it's not a good time to urinate

  • by sending another signal to contract the external urethral sphincter.

  • With about 150 to 200 milliliters of urine inside of it,

  • the bladder's muscular wall is stretched enough

  • for you to sense that there's urine within.

  • At about 400 to 500 milliliters, the pressure becomes uncomfortable.

  • The bladder can go on stretching, but only to a point.

  • Above 1,000 milliliters, it may burst.

  • Most people would lose bladder control before this happens,

  • but in very rare cases,

  • such as when a person can't sense the need to urinate,

  • the pouch can rupture painfully requiring surgery to fix.

  • But under normal circumstances,

  • your decision to urinate stops the brain's signal to the external urethral sphincter,

  • causing it to relax and the bladder to empty.

  • The external urethral sphincter is one of the muscles of the pelvic floor,

  • and it provides support to the urethra and bladder neck.

  • It's lucky we have these pelvic floor muscles

  • because placing pressure on the system by coughing,

  • sneezing,

  • laughing,

  • or jumping could cause bladder leakage.

  • Instead, the pelvic floor muscles keep the region sealed

  • until you're ready to go.

  • But holding it in for too long,

  • forcing out your urine too fast,

  • or urinating without proper physical support

  • may over time weaken or overwork that muscular sling.

  • That can lead to an overactive pelvic floor,

  • bladder pain,

  • urgency,

  • or urinary incontinence.

  • So in the interest of long-term health,

  • it's not a great habit to hold your pee.

  • But in the short term, at least, your body and brain have got you covered,

  • so you can conveniently choose your moment of sweet release.

It begins with a bit of discomfort

Subtitles and vocabulary

Operation of videos Adjust the video here to display the subtitles

B2 US TED-Ed bladder urine pelvic muscular urethra

【TED-Ed】Is it bad to hold your pee? - Heba Shaheed

  • 36658 2543
    韓澐 posted on 2016/10/11
Video vocabulary