[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.51,0:00:07.89,Default,,0000,0000,0000,,Across the whole planet,
Dialogue: 0,0:00:07.89,0:00:13.71,Default,,0000,0000,0000,,humans eat on average between\None and 2.7 kilograms of food a day.
Dialogue: 0,0:00:13.71,0:00:17.53,Default,,0000,0000,0000,,That's over 365 kilograms \Na year per person,
Dialogue: 0,0:00:17.53,0:00:23.07,Default,,0000,0000,0000,,and more than 28,800 kilograms\Nover the course of a lifetime.
Dialogue: 0,0:00:23.07,0:00:27.38,Default,,0000,0000,0000,,And every last scrap makes its way\Nthrough the digestive system.
Dialogue: 0,0:00:27.38,0:00:30.10,Default,,0000,0000,0000,,Comprised of ten organs \Ncovering nine meters,
Dialogue: 0,0:00:30.10,0:00:33.42,Default,,0000,0000,0000,,and containing \Nover 20 specialized cell types,
Dialogue: 0,0:00:33.42,0:00:38.12,Default,,0000,0000,0000,,this is one of the most diverse\Nand complicated systems in the human body.
Dialogue: 0,0:00:38.12,0:00:42.69,Default,,0000,0000,0000,,Its parts continuously work in unison\Nto fulfill a singular task:
Dialogue: 0,0:00:42.69,0:00:45.39,Default,,0000,0000,0000,,transforming the raw materials\Nof your food
Dialogue: 0,0:00:45.39,0:00:48.91,Default,,0000,0000,0000,,into the nutrients and energy\Nthat keep you alive.
Dialogue: 0,0:00:48.91,0:00:51.38,Default,,0000,0000,0000,,Spanning the entire length of your torso,
Dialogue: 0,0:00:51.38,0:00:54.70,Default,,0000,0000,0000,,the digestive system \Nhas four main components.
Dialogue: 0,0:00:54.70,0:00:57.59,Default,,0000,0000,0000,,First, there's the gastrointestinal tract,
Dialogue: 0,0:00:57.59,0:00:59.100,Default,,0000,0000,0000,,a twisting channel \Nthat transports your food
Dialogue: 0,0:00:59.100,0:01:05.62,Default,,0000,0000,0000,,and has an internal surface area\Nof between 30 and 40 square meters,
Dialogue: 0,0:01:05.62,0:01:08.59,Default,,0000,0000,0000,,enough to cover half a badminton court.
Dialogue: 0,0:01:08.59,0:01:09.98,Default,,0000,0000,0000,,Second, there's the pancreas,
Dialogue: 0,0:01:09.98,0:01:10.89,Default,,0000,0000,0000,,gallbladder,
Dialogue: 0,0:01:10.89,0:01:11.68,Default,,0000,0000,0000,,and liver,
Dialogue: 0,0:01:11.68,0:01:16.50,Default,,0000,0000,0000,,a trio of organs that break down food\Nusing an array of special juices.
Dialogue: 0,0:01:16.50,0:01:18.47,Default,,0000,0000,0000,,Third, the body's enzymes,
Dialogue: 0,0:01:18.47,0:01:19.25,Default,,0000,0000,0000,,hormones,
Dialogue: 0,0:01:19.25,0:01:19.100,Default,,0000,0000,0000,,nerves,
Dialogue: 0,0:01:19.100,0:01:20.73,Default,,0000,0000,0000,,and blood
Dialogue: 0,0:01:20.73,0:01:23.20,Default,,0000,0000,0000,,all work together to break down food,
Dialogue: 0,0:01:23.20,0:01:25.09,Default,,0000,0000,0000,,modulate the digestive process,
Dialogue: 0,0:01:25.09,0:01:27.95,Default,,0000,0000,0000,,and deliver its final products.
Dialogue: 0,0:01:27.95,0:01:29.78,Default,,0000,0000,0000,,Finally, there's the mesentery,
Dialogue: 0,0:01:29.78,0:01:32.10,Default,,0000,0000,0000,,a large stretch of tissue that supports
Dialogue: 0,0:01:32.10,0:01:35.85,Default,,0000,0000,0000,,and positions all your digestive organs \Nin the abdomen,
Dialogue: 0,0:01:35.85,0:01:37.83,Default,,0000,0000,0000,,enabling them to do their jobs.
Dialogue: 0,0:01:37.83,0:01:42.15,Default,,0000,0000,0000,,The digestive process begins\Nbefore food even hits your tongue.
Dialogue: 0,0:01:42.15,0:01:44.18,Default,,0000,0000,0000,,Anticipating a tasty morsel,
Dialogue: 0,0:01:44.18,0:01:47.64,Default,,0000,0000,0000,,glands in your mouth start \Nto pump out saliva.
Dialogue: 0,0:01:47.64,0:01:52.13,Default,,0000,0000,0000,,We produce about 1.5 liters\Nof this liquid each day.
Dialogue: 0,0:01:52.13,0:01:53.58,Default,,0000,0000,0000,,Once inside your mouth,
Dialogue: 0,0:01:53.58,0:01:56.06,Default,,0000,0000,0000,,chewing combines with the sloshing saliva
Dialogue: 0,0:01:56.06,0:02:00.87,Default,,0000,0000,0000,,to turn food into a moist lump \Ncalled the bolus.
Dialogue: 0,0:02:00.87,0:02:04.55,Default,,0000,0000,0000,,Enzymes present in the saliva\Nbreak down any starch.
Dialogue: 0,0:02:04.55,0:02:06.22,Default,,0000,0000,0000,,Then, your food finds itself
Dialogue: 0,0:02:06.22,0:02:10.99,Default,,0000,0000,0000,,at the rim of a 25-centimeter-long tube \Ncalled the esophagus,
Dialogue: 0,0:02:10.99,0:02:14.31,Default,,0000,0000,0000,,down which it must plunge \Nto reach the stomach.
Dialogue: 0,0:02:14.31,0:02:16.73,Default,,0000,0000,0000,,Nerves in the surrounding \Nesophageal tissue
Dialogue: 0,0:02:16.73,0:02:20.27,Default,,0000,0000,0000,,sense the bolus's presence \Nand trigger peristalsis,
Dialogue: 0,0:02:20.27,0:02:23.16,Default,,0000,0000,0000,,a series of defined muscular contractions.
Dialogue: 0,0:02:23.16,0:02:25.90,Default,,0000,0000,0000,,That propels the food into the stomach,
Dialogue: 0,0:02:25.90,0:02:29.54,Default,,0000,0000,0000,,where it's left at the mercy\Nof the muscular stomach walls,
Dialogue: 0,0:02:29.54,0:02:32.89,Default,,0000,0000,0000,,which bound the bolus, \Nbreaking it into chunks.
Dialogue: 0,0:02:32.89,0:02:37.02,Default,,0000,0000,0000,,Hormones, secreted by cells in the lining,\Ntrigger the release of acids
Dialogue: 0,0:02:37.02,0:02:39.94,Default,,0000,0000,0000,,and enzyme-rich juices \Nfrom the stomach wall
Dialogue: 0,0:02:39.94,0:02:43.52,Default,,0000,0000,0000,,that start to dissolve the food\Nand break down its proteins.
Dialogue: 0,0:02:43.52,0:02:45.99,Default,,0000,0000,0000,,These hormones also alert the pancreas,
Dialogue: 0,0:02:45.99,0:02:46.70,Default,,0000,0000,0000,,liver,
Dialogue: 0,0:02:46.70,0:02:47.77,Default,,0000,0000,0000,,and gallbladder
Dialogue: 0,0:02:47.77,0:02:49.72,Default,,0000,0000,0000,,to produce digestive juices
Dialogue: 0,0:02:49.72,0:02:53.82,Default,,0000,0000,0000,,and transfer bile, a yellowish-green \Nliquid that digests fat,
Dialogue: 0,0:02:53.82,0:02:56.43,Default,,0000,0000,0000,,in preparation for the next stage.
Dialogue: 0,0:02:56.43,0:02:58.45,Default,,0000,0000,0000,,After three hours inside the stomach,
Dialogue: 0,0:02:58.45,0:03:02.96,Default,,0000,0000,0000,,the once shapely bolus is now\Na frothy liquid called chyme,
Dialogue: 0,0:03:02.96,0:03:05.71,Default,,0000,0000,0000,,and it's ready to move into\Nthe small intestine.
Dialogue: 0,0:03:05.71,0:03:08.24,Default,,0000,0000,0000,,The liver sends bile \Nto the gallbladder,
Dialogue: 0,0:03:08.24,0:03:14.17,Default,,0000,0000,0000,,which secretes it into the first portion of\Nthe small intestine called the duodenum.
Dialogue: 0,0:03:14.17,0:03:17.78,Default,,0000,0000,0000,,Here, it dissolves the fats\Nfloating in the slurry of chyme
Dialogue: 0,0:03:17.78,0:03:22.24,Default,,0000,0000,0000,,so they can be easily digested\Nby the pancreatic and intestinal juices
Dialogue: 0,0:03:22.24,0:03:24.47,Default,,0000,0000,0000,,that have leached onto the scene.
Dialogue: 0,0:03:24.47,0:03:29.53,Default,,0000,0000,0000,,These enzyme-rich juices break the fat\Nmolecules down into fatty acids
Dialogue: 0,0:03:29.53,0:03:33.22,Default,,0000,0000,0000,,and glycerol for easier \Nabsorption into the body.
Dialogue: 0,0:03:33.22,0:03:35.89,Default,,0000,0000,0000,,The enzymes also carry out \Nthe final deconstruction
Dialogue: 0,0:03:35.89,0:03:38.56,Default,,0000,0000,0000,,of proteins into amino acids
Dialogue: 0,0:03:38.56,0:03:40.76,Default,,0000,0000,0000,,and carbohydrates into glucose.
Dialogue: 0,0:03:40.76,0:03:43.90,Default,,0000,0000,0000,,This happens in the \Nsmall intestine's lower regions,
Dialogue: 0,0:03:43.90,0:03:45.89,Default,,0000,0000,0000,,the jejunum and ileum,
Dialogue: 0,0:03:45.89,0:03:49.88,Default,,0000,0000,0000,,which are coated in millions \Nof tiny projections called villi.
Dialogue: 0,0:03:49.88,0:03:54.41,Default,,0000,0000,0000,,These create a huge surface area\Nto maximize molecule absorption
Dialogue: 0,0:03:54.41,0:03:56.99,Default,,0000,0000,0000,,and transference into the blood stream.
Dialogue: 0,0:03:56.99,0:03:59.65,Default,,0000,0000,0000,,The blood takes them on the final\Nleg of their journey
Dialogue: 0,0:03:59.65,0:04:02.45,Default,,0000,0000,0000,,to feed the body's organs and tissues.
Dialogue: 0,0:04:02.45,0:04:04.33,Default,,0000,0000,0000,,But it's not over quite yet.
Dialogue: 0,0:04:04.33,0:04:05.67,Default,,0000,0000,0000,,Leftover fiber,
Dialogue: 0,0:04:05.67,0:04:06.40,Default,,0000,0000,0000,,water,
Dialogue: 0,0:04:06.40,0:04:09.30,Default,,0000,0000,0000,,and dead cells \Nsloughed off during digestion
Dialogue: 0,0:04:09.30,0:04:13.39,Default,,0000,0000,0000,,make it into the large intestine,\Nalso known as the colon.
Dialogue: 0,0:04:13.39,0:04:17.42,Default,,0000,0000,0000,,The body drains out most of the remaining\Nfluid through the intestinal wall.
Dialogue: 0,0:04:17.42,0:04:20.03,Default,,0000,0000,0000,,What's left is a soft mass called stool.
Dialogue: 0,0:04:20.03,0:04:24.03,Default,,0000,0000,0000,,The colon squeezes this byproduct\Ninto a pouch called the rectum,
Dialogue: 0,0:04:24.03,0:04:26.20,Default,,0000,0000,0000,,where nerves sense it expanding
Dialogue: 0,0:04:26.20,0:04:29.19,Default,,0000,0000,0000,,and tell the body when \Nit's time to expel the waste.
Dialogue: 0,0:04:29.19,0:04:32.04,Default,,0000,0000,0000,,The byproducts of digestion\Nexit through the anus
Dialogue: 0,0:04:32.04,0:04:33.47,Default,,0000,0000,0000,,and the food's long journey,
Dialogue: 0,0:04:33.47,0:04:36.52,Default,,0000,0000,0000,,typically lasting between 30 and 40 hours,
Dialogue: 0,0:04:36.52,0:04:38.19,Default,,0000,0000,0000,,is finally complete.