It’s evening, and all I can think about is the rumbling in my tummy and the mouth-watering smells coming out of the oven, where my roommate has a large batch of banana chocolate-chip cookies baking away. And because all I can think about is eating, I’ve decided to give you lovely people a tour of the human digestive process. And because I am such an excellent reporter, I will sacrifice my very own digestive track by eating the entire batch of cookies myself, so I can fully experience the process of digestion.
Let’s start with that desperate feeling of hunger. Is it physical? Psychological? A magical spell put on us by wizards as some form of sick humor? There are many different theories. One scientists inflated a balloon in his own stomach, and relieved a feeling of hunger – but then again, some people who have their stomach removed still report feeling hungry. One thing is for certain – your hypothalamus tells you your hungry, and gets “turned off” when you’re full. (You know that awful feeling after eating too fast? That happens because you’ve eaten so fast that your hypothalamus didn’t have a chance to turn off to adjust to the new influx of food…so you still think you’re hungry)
Now that we’ve decided you’re hungry, you rifle through the cabinets and the fridge (multiple times, expecting the food fairy to make a delivery) and finally settle on something acceptable. And yet, after that first bite, that “something acceptable” tastes like flowers and unicorns and sparkly rainbows. This is because dopamine has just been released in your brain with such a force that it causes a mini-high, and therefore, makes your food taste like heaven. They do say, “hunger is the best seasoning”….
Back to me: so the cookies have been out of the oven for a few minutes, and I can’t resist eating a few at a time. Now I’m chewing away (each bite exerts somewhere between 50 and 200 pounds of force), and breaking down the three gooey, wonderful cookies I just shoved into my mouth. The enzymes in my saliva are further breaking down long chains of starches (basically, lots of carbon and hydrogen), into smaller units.
Then I swallow, and my tongue pushes to the food to the back of my mouth, or the opening of the ten-inch long tube, the esophagus. A flap of skin called the epiglottis hastily covers my windpipe (don’t you hate it when you drink or eat so fast that the epiglottis doesn’t cover your windpipe in time so you just hack and hack and hack?) and the mush, like the first car of a roller coaster perched so precariously at the top of the biggest rise, falls down the esophagus (that noise you hear are the molecules of starch screaming).
After 2-3 seconds of undulating mucus-covered esophageal walls, the food is dropped into my acidic stomach. There, the food is mushed some more, rolled around, and broken down by gastric acid (that stuff that comes up sometimes during a burp and makes your throat hurt), which has a pH between 2 and 4.
The small intestine is where it gets complicated. In that 22-foot long squishy tube, food gets further broken down into proteins, fats, vitamins, and carbs, which are sucked up by the walls of the small intestine, with the help of the pancreas (which secretes digestive enzymes, among other things), the liver (which produces substances that help break down fats and filter out evil things), and the gallbladder (which stores bile for later use).
Then we get to the large intestine. It’s only five feet long, but it’s wider than the small intestine. The watery mix squeezes through the large intestine, which sucks up water and any other leftover nutrients from what used to be those delectable banana chocolate-chip cookies. The waste gets more and more solid (yup, you know what comes next) as the water is getting vacuumed out of it. The waste is stored in the rectum, until…oh, excuse me, I’ll be right back.
And there you have it! The digestive track! Of course, the biggest miracle of all is that even though I’m completely jeans-button-popping stuffed and feeling the need to hit the gym, in 12 hours I’ll wake up to my stomach grumbling grumpily once again.