1. Unit 5 – Anatomy & Physiology
The Digestive System

2. Objectives By the end of the lesson you will be able to:-
- Describe the passage through the digestive tract, using at least 4 anatomical terms.
- Explain the function of 4 organs of the digestive system

3. Key Terms
Digestion
Absorption
Ingestion
Egestion

4. Try This

5. Watch video clip and produce overview of pathway
Pathway of food through digestive system

6. What is Digestion?
Digestion is the process by which food and drink are broken down into their smallest parts so that the body can use them to build and nourish cells and to provide energy.

7. Digestions Mechanical Digestion Chemical Digestion
involves food being ground up, for example by the teeth and by the churning movements of the alimentary canal.
involves large molecules being broken down into small ones, by enzymes.

8. We make 1 – 3 pints
of saliva a day

9. Food moves down the oesophagus by peristalsis.

10. Stomach
Food is broken down & mixed with gastric juice to produce chyme
Hydrochloric acid kills bacteria & provides optimum pH for enzymes.

11. Small Intestine Food is released a little at a time, from the stomach.
Long structure allows for further digestion & absorption to take place.
95% of food is absorbed here.

12. The Small intestine
is Approx
6 – 7 metres
in length

13. Large Intestine
The first part is the colon, here water is reabsorbed into the blood.
The indigestible remains form semi solid faeces which is stored in the rectum until being passed out of the body through the anus.

14. 400 Species of Bacteria
live in the colon

15. Pancreas & Liver

16. Liver & Pancreas Liver Pancreas Largest organ in the body;
Produces bile which emulsifies fats;
Removes glucose from the blood & converts to glycogen for storage.
Slim, leaf-shaped gland;
Secretes enzymes which breakdown proteins, fats & carbohydrates.

17. Digestion Food stays in stomach for 3-4 hours
It spends 6 – 7 hours in the intestine
Process completed within 12 to 24 hours.

18. Activity
Complete the Digestive Juices & their Function Worksheet

19. Use these words to complete the sheet!
Glucose
Starch
Food
Bacteria
Stomach
Fats
Lactose
Lipids
Sucrose
Acids
Vitamin B12
Amino acids
amino
Peptides
Carbohydrates

20. Further Reading
Ross and Wilson: anatomy and physiology in health and illness (9th edition)
Tortora, G. ( 1996) Principles of anatomy and physiology (8th Edition ed.)