DK - WOW! The Visual Encyclopedia of Everything

69

DIGESTIVE SYSTEM

▶

The body needs nutrients for energy, growth, and repair. The digestive system breaks down food to release these essential nutrients. The system consists of the mouth and teeth, the oesophagus (a muscular tube leading from the mouth to the stomach), the stomach, and the small and large intestines. Food is digested using mechanical force, such as chewing, and through chemical digesters called enzymes. Nutrients are then absorbed into the blood and carried to the body’s cells.

URINARY SYSTEM

▶

Consisting of the kidneys, ureters, bladder, and urethra, the urinary system makes urine and removes it from the body. The kidneys make urine by removing wastes and excess water and salts from the blood, thereby keeping its composition constant. Urine

is stored in the bladder and expelled through the urethra

at its base.

The large intestine turns waste into faeces (poo) and pushes them out of the body The small intestine is a long tube in which most digestion and absorption occurs

Each kidney contains a

million tiny filtering

units that process

blood to make urine

▲

LIVER

The largest internal organ, the liver controls the composition of the blood, processing nutrients newly absorbed

from the small intestine.

Bladder is a muscular bag that, when filled, pushes urine out through the urethra

◀

STOMACH

This muscular bag

expands as it receives

and stores food that has

been chewed and swallowed. During storage the stomach’s

walls churn food into a part-digested “soup”,

which is released

into the small

intestine.

PANCREAS

▶

Liver stores excess glucose and releases The pancreas releases chemicals called enzymes into the small intestine to aid digestion, and hormones (chemical messengers) into the blood to control levels of glucose – the body’s main fuel – in the blood.

it when

the body

needs it

The gall bladder

stores bile, a fluid that

aids fat

digestion

Billions of harmless bacteria digest waste in the large intestine

Ureter has muscular walls that squeeze urine downwards to the bladder

068_069_Organs.indd 69 03/01/19 12:09 PM