Transcript 8A1 Food - Chemactive

8A4 The digestive system
Name the organs.
Click to reveal the answers.
stomach
oesophagus
small intestine
large intestine
rectum
What does the digestive system do?
• Breaks up food into smaller pieces.
• Breaks up proteins, carbohydrates and fats
into smaller molecules.
• Absorbs the smaller fragments and vitamins,
minerals and water.
• Gets rid of food that cannot be digested and
other wastes.
The digestive system
• The substances in foods
must be digested before
they can be used by the
body.
• Digestion happens in the
mouth, the stomach and
the small intestine.
• Food is pushed along the
gut by peristalsis.
• Food is broken up by
physical and chemical
processes.
• Small food molecules
pass into the blood in the
small intestine.
How does digestion work?
Teeth and jaws
crush food
Saliva breaks down
starch and coats
food
Food is pushed
down
oesophagus by
peristalsis
Gastric juices
from the pancreas
complete digestion
in the small intestine
Acid and gastric
juices in the
stomach break
up proteins
Stomach muscles
churn food into
a paste
Food materials are
absorbed by villi
in the small intestine
Water is absorbed
in the
large intestine
Faeces are stored
in the rectum and
pushed out of
the anus
The model gut
• What do you predict will happen?
• How will you detect starch or glucose?
• The tubing is a model intestine, the starch and sugar is
model food. What is the warm water round the tube a
model of?
Key words
Do you know what these sentences describe?
Click to reveal the answers.
Method of pushing food down the gullet
peristalsis
Finger-like extension in the small intestine
villus
Organ that makes gastric juices
pancreas
Wastes stored in rectum
faeces
Name the parts
Click to reveal the answers.
salivary glands
oesophagus
small intestine
rectum
teeth
stomach
large intestine
anus