Yr8 - digestive system

Dr Pusey

www.puseyscience.com

Digestive System The digestive system breaks

down the food you eat into small pieces that your cells can use (‘cell food’)

Digestion = process of breaking down food

There are two different types of digestion – mechanical andchemical

Digestion Mechanical – crushing the food

into smaller pieces. A physical change, no new substances made.

Chemical – food is chemically broken down into smaller molecules. Chemical change, new substances are made.

Digestive System The digestive system is made

up of organs, including:

Mouth – salivary glands

Esophagus

Stomach

Pancreas

Small intestine

Large intestine

Mouth Teeth – crush the food and break it

into smaller bits, mechanical digestion.

Salivary glands – make saliva. Saliva helps break food down and makes it slippery so it’s easy to swallow. Chemical digestion.

Tongue – helps move the food around your mouth. Rolls the food into a ball called the bolus.

Esophagus Esophagus is the long tube that

connects your mouth to your stomach.

The muscles of the esophaguspush the bolus from the mouth to the stomach.

This process is called peristalsis.

Stomach The stomach is full of gastric

juice

The gastric juice breaks down the food through chemical digestion

The stomach also churns (moves around) and breaks down the food through mechanical digestion

Small Intestine The small intestine absorbs nutrients

from the food into the blood stream

Juices from the liver, pancreas and gall bladder enter the digestive system here, they help with chemical digestion

The inside of the small intestine is covered in villi, these are tiny fingers which help absorb the nutrients

Your small intestines are up to 6 m long!

Pancreas, Liver, Gallbladder

3 Separate Organs

Not part of the pathway

Liver makes Bile

Gallbladder Stores Bile

Pancreas Make Pancreatic Juice

Bile and Juice designed to further break down your food as it passes through the small intestine

Villi

Large Intestine No digestion actually happens

in the large intestine

The large intestine just absorbs water back into the body

Your large intestine is only 1.5 m long!

It’s called the large intestine because it is wider than the small instestine

Complete!

Faeces

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