Digestion- foundation level

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Experiment

A dentist would write your dental records as

I: 2/2 C:1/1 PM:2/2 M:3/3

What do you think this means?

What is your dental record?

If you do not have a full set of teeth, can you explain why some teeth are missing?

Slide 20

Tooth decay

What do you think causes tooth decay?

Saliva is normally slightly alkaline. When we eat, bacteria in our mouth feed on sugar and turn it into acid. The sugar starts to attack the enamel and wear it away.

Slide 21

Tooth decay

Decay has started in the enamel

NO PAIN

Decay has reached the dentine

SLIGHT

TOOTHACHE

Decay reaches the pulp

SEVERE

TOOTHACHE

Decay has spread down to the nerve root

EXCRUCIATING

PAIN!!

Slide 22

Preventing Tooth Decay

How can we prevent tooth decay?

How well do you brush your teeth?!

What sort of foods should you avoid?

Design a poster for a Year 7 student explaining what causes tooth decay and how to avoid it.

Slide 23

Tour guide

Mouth

Teeth √

Amylase enzyme (What are enzymes???)

Oesophagus

peristalsis

Stomach

Protease enzyme

Enzymes and pH

Pancreas

Amylase, Protease and Lipase Enzymes

Small intestine

Amylase, Protease and Lipase Enzymes

Absorption

Large intestine

egestion

Slide 24

Enzymes

Remember :

Large particles cannot be absorbed in the small intestine

starch

starch

starch

starch

G

G

G

GUT

INSIDE THE BODY (BLOOD)

Large particles (e.g. starch) are left in the gut and small particles (e.g. glucose) go through into the blood.

G

G

G

BUT large particles can be broken down into small particles. This is called DIGESTION

Slide 25

Enzymes

They need to be broken down chemically by ENZYMES.

Enzymes are biological catalysts. They speed up chemical reactions in the body.

Digestive enzymes speed up the breaking down process by holding the substrate (the large particle to be broken down) in place

Slide 26

The enzyme fits over the substrate perfectly – like a key fits a lock.

It holds the starch molecule in place as a water molecule breaks the bond between two glucose particles

Starch molecule

Amylase enzyme

Slide 27