The New Childrens Encyclopedia

The pancreas

constantly releases

digestive juices into

the small intestine.

Food enters the

mouth where the

tongue assesses

whether it is sweet,

savory, hot or cold.

FOOD FLOW

287

Food is swallowed

and passes into the

esophagus. It is

moved by muscle

contractions called

peristalsis.

BEYOND THE STOMACH

After leaving the stomach, food

enters the small intestine. This is

where nutrients are absorbed

from the food for use by your

body. Material that isn’t digested

passes into the large intestine,

where it’s turned into feces.

The small intestine is a

long tangled tube that

produces many

different enzymes to

digest food. The tube

is covered inside

with tiny, fingerlike

projections called

villi. These

increase the

intestine’s surface

area for the

absorption

of nutrients.

The large intestine is where

the last nutrients are extracted,

together with water. Undigested

material is combined with

other waste products and

moved on to the

rectum before

passing out of

the body.

Built-in protection

The stomach wall is deeply

folded and pitted. Mucus

is constantly secreted to

prevent the stomach’s

acids from digesting itself.

Mucus

The large

intestine is

wider than the

small intestine.

The gall bladder stores

bile, a digestive juice.

Bile is used to break

down fats.

The liver is thought to have

more than 250 different

functions. Among these, it

processes nutrients, removing

what your body needs. It also

stores glucose (which gives you

energy) and breaks down

harmful substances.

Why does your stomach

“growl” when empty? If you are

hungry, your stomach receives

signals from the brain to begin

digestion. The muscles begin to work

and acid is mixed in the stomach

without food. This produces

vibrations we hear as growls.

7

/^7 

O
 The stomach can store about

3 pints (1.5 liters) of food.

O
 A meal takes 18–30 hours to

pass through the human body.

O
 The small intestine is about

17 ft (5 m) in length.

O
 The large intestine is about

5 ft (1.5 m) in length.

O
 The liver, the body’s largest

internal organ, produces about

2 pints (1 liter) of bile a day.

O
 The large intestine contains

millions of bacteria.

FAST FACTS: DIGESTION

SOLID OR LIQUID

Solid food takes longer

to break down, which

means that a meal stays

in the stomach for much

longer than a drink,

which may pass through

in minutes.

THE HUMAN BODY

Gastric pit