1. Enzymes and the digestive
system
Objective: To understand the structure and
function of the major parts of the digestive
system.
Outcomes:
~ Identify the structures found in the digestive
system and describe their function.
~ Explain how both physical and chemical processes
are involved in digestion.
~ Explain the role of enzymes in the digestive
system.
Sunday, 28 September 2014
Keywords
Enzymes
Digestion
Absorption
Egestion
Assimilation
Carbohydrases
Lipases
Proteases
Hydrolysis

2. The Digestive
Mouth (containing System
salivary glands)
Liver
Oesophagus
(Gullet)
Stomach
Pancreas
Large
intestine
Gall bladder
Small
intestine
Rectum
Anus

3. Organ Function
Churns up food with hydrochloric acid.
Undigested food passes along here and water is
reabsorbed.
Makes bile which is then stored in the gall bladder.
Digested food is absorbed into the blood here.
Makes enzymes.
Squeezes food towards the stomach.
Breaks food into smaller pieces.

4. The alimentary canal along with a range of organs and glands (produce
enzymes) make up the digestive system.
Function?
To break down large
insoluble molecules of
food into smaller soluble
ones.
~ Physical digestion
~ Chemical digestion (enzymes)
e.g. carbohydrate
 glucose
Peristalsis
Involuntary waves of
muscular contraction

5. The mouth
Physical digestion of food by the
teeth and tongue, forming a
bolus.
Salivary glands secrete saliva:
~ water-dissolves any soluble
substances
~ mucus-lubrication
~ lysozymes- kill bacteria
~ amylase-digests starch into
maltose (chemical digestion)

6. The oesophagus
A muscular tube connecting
the mouth to the stomach.
Peristalsis
No digestion occurs here.
Mouth
Oesophagus Trachea
Lungs
Stomach
Thick muscular wall

7. The stomach
Physical digestion occurs due to
muscles in the stomach which
churns the food forming chyme.
Gastric glands secrete gastric
juice:
~ Enzymes (proteases) provide
chemical digestion.
~ HCl acid (pH1) to kill bacteria.
~ Mucus to prevent the stomach
from being digested.

8. The pancreas Large gland which secretes pancreatic
juice.
This contains enzymes including lipase,
protease and amylase.
Stomach
Pancreas
Gall bladder
Duct
Duct
Small intestine

9. The small intestine Long muscular tube (6.5m)
~ Duodenum: Further digestion
takes place here due to enzymes
secreted by the intestine walls and
from pancreatic juice. Bile is also
secreted here via the liver, which
emulsifies fats and neutralises
stomach acid.
~ Jejunum: Digestion and
absorption. Surface area is
increased due to villi and microvilli.
~ Ileum: Final digestion and
absorption.

10. The large intestine
Where most water is
reabsorbed.
Food becomes drier forming
faeces.
Stored in the rectum and
released via the anus,
egestion.
Transverse colon
Ascending
colon
Descending
colon
Rectum
Appendix
Anus

11. Chemical digestion
Chemical digestion is...
Physical digestion V s.
List 2 places where
this type of
digestion occurs.
Large molecule? Small
molecule?
Group of
enzymes
involved?
Carbohydrates
Proteins
Fats
Hydrolysis is...
Copy and complete the table below.
Following digestion small molecules are...
Describe the
importance of this
type of digestion.

12. Digestive System: Recap Digestive System: Recap
Organ Function
Churns up food with hydrochloric acid.
Undigested food passes along here and water is
reabsorbed.
Makes bile which is then stored in the gall bladder.
Digested food is absorbed into the blood here.
Makes enzymes.
Squeezes food towards the stomach.
Breaks food into smaller pieces.
Organ Function
Churns up food with hydrochloric acid.
Undigested food passes along here and water is
reabsorbed.
Makes bile which is then stored in the gall bladder.
Digested food is absorbed into the blood here.
Makes enzymes.
Squeezes food towards the stomach.
Breaks food into smaller pieces.