WEBVTT - How Does the Larynx Work? 0:00:01.920 --> 0:00:06.400 Welcome to brain Stuff production of I Heart Radio, Hey 0:00:06.440 --> 0:00:09.800 brain Stuff, Lauren Vogel Bomb here. The larynx may not 0:00:09.920 --> 0:00:12.879 get the same amount of attention as the heart or lungs, 0:00:12.880 --> 0:00:16.680 but it's still an important internal organ nestled in the 0:00:16.720 --> 0:00:20.120 necks of people and other animals. The larynx helps allow 0:00:20.160 --> 0:00:24.079 for noisemaking and speech, and is located below the epiglottis, 0:00:24.239 --> 0:00:27.000 which is the leaf shaped flap that prevents choking by 0:00:27.080 --> 0:00:30.720 keeping food and drink out of the lungs. Part of 0:00:30.720 --> 0:00:34.400 the larynx structure includes the voice box, also sometimes referred 0:00:34.440 --> 0:00:37.519 to as the vocal chords. It's what makes up the 0:00:37.560 --> 0:00:39.760 bump that you can see and feel in the middle 0:00:39.800 --> 0:00:43.839 of your neck, scientifically known as the laryngeal prominence, but 0:00:44.080 --> 0:00:47.919 more commonly called the Adam's apple. Women have one too, 0:00:48.240 --> 0:00:52.320 just often less pronounced. During childhood, the voice boxes of 0:00:52.360 --> 0:00:55.040 boys and girls are about the same size, but when 0:00:55.080 --> 0:00:57.840 most boys hit their tween and teen years, their vocal 0:00:57.880 --> 0:01:01.560 chords hit a growth spurt. The growth causes their voices 0:01:01.560 --> 0:01:04.479 to crack and eventually results in a deeper and more 0:01:04.520 --> 0:01:09.640 resonant tone. So let's look at how the voice box 0:01:09.760 --> 0:01:14.399 or vocal chords work. First off, neither moniker is really accurate. 0:01:14.920 --> 0:01:18.440 The vocal chords are actually two bands of flexible, smooth 0:01:18.480 --> 0:01:21.440 muscle tissue that are located in the larynx, and these 0:01:21.520 --> 0:01:24.440 muscles vibrate as air moves through them on its way 0:01:24.480 --> 0:01:28.399 to or from the lungs. They're more properly called folds 0:01:28.520 --> 0:01:32.919 instead of chords. We spoke via email with gi Zeppe 0:01:33.000 --> 0:01:37.360 Araguna m D. He explained during sound production, the vocal 0:01:37.360 --> 0:01:40.959 folds closed together and start vibrating as air is expelled 0:01:41.000 --> 0:01:43.840 from the lungs and passes between them and into your mouth, 0:01:44.200 --> 0:01:46.360 which helps to make the sounds we hear when we're 0:01:46.360 --> 0:01:50.800 listening to people talk. So, the larynx is made up 0:01:50.840 --> 0:01:54.680 of a cartilage skeleton that contains the vocal folds covered 0:01:54.720 --> 0:01:58.240 by a mucous lining. The folds are extremely adept at 0:01:58.280 --> 0:02:01.640 changing shape, position, and mention, so the voice can make 0:02:01.680 --> 0:02:04.720 a range of sounds at a variety of levels. If 0:02:04.760 --> 0:02:07.960 the larynx becomes inflamed because of illness or injury, the 0:02:08.040 --> 0:02:12.040 vocal chords can swell and cause laryngitis, which is characterized 0:02:12.040 --> 0:02:15.160 by a hoarse, gravelly sounding voice or the loss of 0:02:15.160 --> 0:02:19.520 one's voice altogether. But we also spoke by email with 0:02:19.560 --> 0:02:23.040 Taylor Graber m d. He said, if they're swelling to 0:02:23.080 --> 0:02:26.919 a vocal chord from overuse, cancers, or trauma, the tone 0:02:26.960 --> 0:02:30.440 and function produced by the vocal cord becomes altered. The 0:02:30.480 --> 0:02:33.520 sounds can also change by injury to the muscles or 0:02:33.560 --> 0:02:36.480 to the nerves that innervate or give sensation to the 0:02:36.560 --> 0:02:41.320 vocal chords. However, there are several sounds that we can 0:02:41.360 --> 0:02:46.400 produce without a larynx, even speech via whispering. When you whisper, 0:02:46.560 --> 0:02:50.160 the vocal chords can stay slack and not vibrate. But 0:02:50.280 --> 0:02:52.960 this is known as an open throat whisper, and it 0:02:53.000 --> 0:02:56.320 allows people who are mute to make sound. It's also 0:02:56.360 --> 0:02:59.160 a helpful technique for people who are resting their voices, 0:02:59.200 --> 0:03:02.400 such as singers sore those with a sore throat. However, 0:03:02.720 --> 0:03:06.960 most people don't use this passive technique when they whisper. Instead, 0:03:07.040 --> 0:03:09.760 they strain to produce a sound, and this can be 0:03:09.840 --> 0:03:14.480 just as harmful to the vocal cords as shouting. But hey, 0:03:14.520 --> 0:03:17.959 if humans and other animals all have a larynx, then 0:03:18.000 --> 0:03:22.720 why is speaking a uniquely human ability. Our brain formation 0:03:22.760 --> 0:03:25.240 has something to do with it, but people have an 0:03:25.360 --> 0:03:29.600 especially complex system comprising the larynx which produces sound, and 0:03:29.840 --> 0:03:33.960 a flexible mouth, tongue, and lips that, in combination, allows 0:03:34.040 --> 0:03:38.040 us to generate the precise sounds that language requires. When 0:03:38.040 --> 0:03:40.880 we talk, air moves from the lungs through the larynx, 0:03:40.920 --> 0:03:44.040 and that sound is shaped by the extreme fine motor 0:03:44.080 --> 0:03:48.920 control found in the throat, mouth, tongue, and lips. We 0:03:49.000 --> 0:03:51.840 also have a bone called the highoid. This is a 0:03:51.960 --> 0:03:54.720 U shaped bone situated at the front of throat above 0:03:54.760 --> 0:03:58.280 the larynx. According to Graber, he said it forms the 0:03:58.280 --> 0:04:01.200 attachment from multiple muscles and the neck, which aid in 0:04:01.320 --> 0:04:06.800 tongue movement and swallowing. What's really unusual about this larynx 0:04:06.800 --> 0:04:09.480 related bone is that it has the distinction of being 0:04:09.480 --> 0:04:12.160 the only bone in the human body that's free floating, 0:04:12.520 --> 0:04:15.720 which means it isn't connected to any other bone. Instead, 0:04:15.800 --> 0:04:19.559 it's supported by connective tissue. The hyoid is only found 0:04:19.560 --> 0:04:22.080 in humans and Neanderthals and is believed to be the 0:04:22.120 --> 0:04:26.679 foundation of our ability to speak. There are about sixty 0:04:27.040 --> 0:04:29.560 people in the United States who have had their larynx removed, 0:04:29.680 --> 0:04:32.440 but only a few who have had a larynx transplant. 0:04:32.880 --> 0:04:35.680 A few people qualify, and if they do, the surgery 0:04:35.760 --> 0:04:38.960 is complex that takes about eighteen hours, and is hampered 0:04:39.000 --> 0:04:44.039 by shortage of larynx available to transplant. However, new initiatives, 0:04:44.120 --> 0:04:47.159 including lap grown and three D printed larynx, have the 0:04:47.160 --> 0:04:55.880 potential to help people recover their own voices again. Today's 0:04:55.880 --> 0:04:58.040 episode was written by Laurie al Dove and produced by 0:04:58.040 --> 0:05:00.280 Tyler Klang. For more in this and not of other 0:05:00.360 --> 0:05:03.559 craft topics, visit how stuff works dot com. Brain Stuff 0:05:03.600 --> 0:05:06.080 is production of I Heart Radio or more podcasts. My 0:05:06.120 --> 0:05:09.040 heart Radio visit the iHeart Radio app, Apple Podcasts, or 0:05:09.080 --> 0:05:10.880 wherever you listen to your favorite shows.