What Happens to Food After You Eat It? Human Digestive System

What You'll Learn

• The esophagus pushes food to the stomach with muscle waves called peristalsis — it even works upside down
• The stomach churns food like a mixing machine with acid and enzymes
• The small intestine is about 23 feet (7 meters) long — "small" means narrow, not short — and it's where most nutrients get absorbed into the blood
• The liver makes bile, the gallbladder stores it, and the pancreas sends enzymes to help
• The large intestine absorbs leftover water, and helpful bacteria live there
• Whatever the body can't use leaves as waste

Words to Know

Digestion

Your body breaking food into tiny pieces it can use

Digestion turns a sandwich into fuel for running and thinking.

Saliva

The spit in your mouth that moistens food and starts breaking it down

Saliva makes dry crackers easier to swallow.

Enzyme

A tiny helper that snips food into smaller pieces

Enzymes in the small intestine break bread into sugars.

Peristalsis

The squeeze-and-relax muscle waves that push food down

Peristalsis moves food even if you're hanging upside down.

Esophagus

The stretchy tube that carries food from mouth to stomach

The bite slid down my esophagus to my stomach.

Small intestine

The long narrow tube where most nutrients get absorbed

The small intestine is about 23 feet long in a grown-up!

Absorb

When nutrients pass through the intestine wall into your blood

The small intestine absorbs nutrients like a sponge soaking up juice.

Large intestine

The wider tube that absorbs leftover water

The large intestine saves the water your body still needs.

Bile

A juice your liver makes that breaks up fat

Bile splits big fat blobs into tiny droplets.

Check What You Learned

Fun Facts

• Digestion begins in the mouth: teeth mash and grind food, and saliva moistens it while enzymes like amylase begin breaking down carbohydrates

  Source: Britannica Kids / NIH NIDDK

• The esophagus moves food to the stomach by peristalsis — waves of muscle squeezing and relaxing — which works even when you're upside down

  Source: NIH NIDDK

• The stomach churns food with strong muscles while stomach acid and enzymes break it into a soupy mix called chyme

  Source: NIH NIDDK

• An adult's small intestine is about 20–23 feet (6–7 meters) long — it is called "small" because it is narrow, not because it is short

  Source: Britannica / NIH NIDDK

• The liver makes bile, the gallbladder stores it, and the pancreas sends digestive enzymes into the small intestine

  Source: NIH NIDDK

• Enzymes break carbohydrates into simple sugars, proteins into amino acids, and fats into fatty acids

  Source: NIH NIDDK