How the Digestive System Works | 3D Animation

Digestion begins the moment you take a bite. Food is shuttled from the mouth to the stomach via the esophagus, a ride that will take about 5-8 seconds. The peristalsis is the involuntary muscular force that propels food  through the digestive tract.

It almost looks like an ocean wave pushing food from one organ to the next. When food reaches the end of your esophagus, a ringlike muscle called the lower esophageal sphincter relaxes and lets the food pass into your stomach. Weakness of this sphincter causes a back-flux of stomach acid and heartburn.

The stomach is where the real action begins. Digestive juices and enzymes break down the food that you swallowed. This helps make nutrients available for absorption later in the small intestine.

The digestive juices are powerful hydrochloric acids that kill pathogens in food and give the stomach the low pH digestive enzymes need. This acid could literally dissolve most of the other organs in your body. Luckily, your stomach contains a thick mucous lining.

However, when there’s too much acid in the stomach, it can eat away the inner surface of the stomach, causing an ulcer. The process of digestion takes longer for some types of foods than others. Simple carbohydrates such as an energy drink break down the fastest.

This explains why many recommend energy drinks for a quick energy boost. Proteins take longer to digest, and fats take the longest time of all. The stomach slowly empties its contents – which now has the consistency of oatmeal – into your small intestine.

The muscles of the small intestine mix food with digestive juices from the pancreas, liver, and intestine and push the mixture forward for further digestion. The walls of the small intestine are covered by tiny finger-like projections called villi. These projections increase the surface area through which nutrients can be absorbed into your bloodstream.

As peristalsis continues, the waste products of the digestive process move into the large intestine. The large intestine is named for the diameter of the cavity, not for its length. It is actually much shorter than the small intestine.

Its role is to absorb any extra water from the digested material before  it is finally excreted. If food passes through too quickly, too little water is absorbed, and you might have diarrhea. If it passes too slowly, your body absorbs too much water, and you may become constipated.

It takes about 30 hours for food to move through the large intestine. All in all, the whole process — from the time you swallow food to the time it leaves your body as feces — takes about two to four days. Solid waste is characteristically brown and stinky.

Do you know what causes its odor? If you guessed that bacteria are involved, you’d be right. Microbes that reside in the large intestine make a meal of the leftovers  from the small intestine.

The smell associated with stool comes from the gases released by bacteria. The large intestine then empties its contents into the rectum. Its job is to let you know that there is a stool to be evacuated and to hold the stool until that evacuation happens.

Thank you for watching this video. If you want to learn more about how our heart or lungs work, please take  a look at my next video.