This is Bob.

Just like you and me, Bob likes to eat food.
When Bob eats food, it passes through his digestive system.
Let's watch Bob eat a magical blob of food.

Mouth & Esophagus

When the magical blob enters Bob's mouth, he uses his teeth to break it down into smaller pieces. This is called mechanical digestion. Those two orange things on each side of Bob's mouth are his salivary glands. These release salivary amylase which helps to break down the magical blob before it reaches his stomach. The tube that the magical blob is in is Bob's esophagus and the magical blob is now called a bolus, but we'll call it a magical bolus. Bob's esophagus uses muscles to move the magical bolus down in a process called peristalsis. Oh, and the magical bolus has to first pass through Bob's pharynx before entering the esophagus. The pharynx stops food from entering Bob's trachea (a.k.a. his windpipe).



The magical bolus is now inside Bob's stomach which it entered from his esophagus through the cardiac sphincter and is now called chyme , but we'll call it magical chyme. The yellow-ish liquid you see the magical chyme floating on is a mixture of various substances, one of which is hydrochloric acid that is produced by pepsin in his stomach. These digestive juices break down the magical chyme using chemical digestion. Lucky for Bob, the inside of his stomach is covered in a layer of mucus, preventing the digestive juices from damaging his stomach. Ignore all of the other things you see for now, we'll explain them in a second.


Accessory Organs

Accessory organs are organs which the magical chyme doesn't actually pass through, but instead they help out other organs with the digestion.The magical chyme leaves the stomach through the pyloric sphincter on the bottom and heads towards the intestines. But first, the magical chyme is soaked with a substance called bile which is created by the liver, the large red organ. The bile is stored in the gallbladder which is that green sac you see.

Additionally, the curly purple-coloured organ you see is Bob's pancreas. The pancreas is very important since it releases quite a few substances. Bicarbonate is released in order to neutralize the acid from the stomach; trypsin is released in order to break down proteins into peptides; pancreatic amylase is released in order to break down carbohydrates into a sugar called maltose; and lipase is released in order to break down lipids (a.k.a. fats) into smaller pieces.


Small Intestine & Celiac Disease

The magical chyme is now in Bob's small intestine which is the tangled blue tube you see. Fun fact: Bob's small intestine is about 7 metres long meaning it would probably be taller than your house if it was stretched out. Anyways, once the magical chyme is in there, the peptides broken down earlier from the proteins by the pancreas get broken down further into amino acids by peptidases. The maltose broken down earlier is now also broken down further into glucose by maltase. The inside walls of the small intestine are covered in little hairs called villi shown in the first close-up. Bob's villi are covered in even smaller hairs called microvilli, shown in the second close-up, which is where all of the nutrients are absorbed into Bob's body. The microvilli also contain lacteals which absorb things like fats.

Unfortunately, Bob has Celiac Disease. This means that the inner walls of Bob's small intestine have been damaged by something called gluten which is a glue-like substance found in foods like bread. This causes Bob's intestines to absorb less of the nutrients in his food which can cause symptoms such as anemia, diarrhea, weight loss, tiredness, cramps, bloating, and being angrier than usual. There's no cure for the disease, so people like Bob have to eat gluten-free foods to prevent any further damage to their small intestine. We like Bob, so the magical blob of food we gave him was gluten-free.


Large Intestine

The orange tube that the magical chyme is now inside is Bob's large intestine. Some extra nutrients left over from the small intestine are absorbed in here. Also, any water that the magical chyme contains is absorbed here and added to Bob's body, making the magical chyme much harder than it was before. The large intestine is much shorter than the small intestine and so it spends less time in here. When magical chyme gets to the end of the tube, Bob feels the need to get to the bathroom. In a bathroom or not, the magical chyme leaves Bob's body through the orange tube at the bottom called the rectum.


The End.

Now that Bob has taken what he needs from the magical blob, it has left his body.
Unfortunately for Bob, he wasn't able to find a bathroom in time.
We decided not to show you what happened, but you can probably figure it out yourself.