1. MENU OF THE DAY
Describe the functions of main regions of the alimentary canal and the associated organs: mouth, salivary glands, oesophagus, stomach, duodenum, pancreas, gall bladder, liver, ileum, colon, rectum, anus, in relation to ingestion, digestion, absorption, assimilation and egestion of food, as appropriate.
Functions of a typical amylase, protease and lipase (listing the substrate and end-products)

2. Nutrition in animals

3. How does…..

4. “ You are what you eat.” - Jean Anthelme Brillat-Savarin

5. Holozoic nutrition
Holozoic nutrition: feeding on ready- made complex organic matter.

6. What is Nutrition?
The taking in of food (chemical energy) by the body & converting it into living matter

7. 5 processes in digestion
INGESTION
Taking in food
Breakdown of complex
food substances into smaller
soluble food substances
DIGESTION
ABSORPTION
Digested food is absorbed
Into body cells
Absorbed food is use to
provide energy or form
new protoplasm
ASSIMILATION
EGESTION
Removal of undigested food

8. Feeding/ Ingestion
Feeding/ Ingestion – intake of food into the mouth.

9. Digestion
Digestion – large food molecules are broken down into small, soluble and diffusible molecules.
2 types: Physical and chemical digestions

10. 2 types of digestions
Physical digestion refers to the mechanical break up of food into small particles which increases its surface area for chemical digestion. (E.g. Chewing, stomach churning). It also mix the digestive enzymes with the food particles

11. 2 types of digestions
Chemical digestions – breaking of biomolecules like proteins, starch and fats into small soluble molecules which can be absorbed by the cells. It involves digestive enzymes and chemical reactions like hyrolysis.

12. Why must food molecules be broken down into smaller, simpler forms before it can be absorbed by the cells for other uses?
Cell membranes are partially permeable and only allow small molecules to pass through.
e.g. glucose must pass through the cell membrane to reach the mitochondria so as to release energy in tissue respiration
e.g. amino acids must pass through the cell membrane to reach the ribosomes to synthesise proteins.

13. Absorption
Absorption – digested food materials are taken into the body cells.

14. Assimilation
Assimilation – absorbed food materials are converted into new protoplasm or used to provide energy.

15. Do not confuse Ingestion with Egestion!!!
Egestion – elimination of undigested food materials (faeces)
Do not confuse Ingestion with Egestion!!!

17. Digestive enzymes Starch Proteins Lipids/ Fats maltose amino acids
AMYLASE
Starch
maltose
PROTEASE
Proteins
amino acids
LIPASE
Lipids/ Fats
fatty acids &
glycerol

18. Alimentary canal

19. The Digestive System Consists of:
1) The gut or alimentary canal (9 m) from mouth to anus.
2) Glands (A cell, tissue, or organ that secretes a chemical substance).
3) Associated organs.

20. Mouth and buccal cavity
The Alimentary Canal
Mouth and buccal cavity
Oesophagus
Stomach
Small intestines
Large intestine
Anus

21. Mouth & Buccal Cavity

22. The Mouth & Buccal Cavity

23. The Mouth & Buccal Cavity
Food enters through the mouth. This process is called ingestion.
Teeth cuts food into small pieces. This increases surface area to volume ratio for enzyme to act more efficiently.

24. The Mouth & Buccal Cavity
Salivary glands produce saliva to moisten food.
Saliva also contains salivary amylase to break down starch to maltose.
pH of saliva is neutral (around pH 7).

25. The Mouth & Buccal Cavity
Salivary Glands

26. The Mouth & Buccal Cavity
Salivary Amylase
Starch Maltose
Salivary amylase is active at pH 7.

27. The Mouth & Buccal Cavity
Tongue rolls food into boli.
Food is swallowed and enters the pharynx.

28. Human Alimentary Canal
Made up of a tubular gut called the alimentary canal.
Food travels through our body along the alimentary canal which is a continuous tube beginning at the mouth and ending at the anus.
The parts of the gut includes: mouth, pharynx, oesophagus, stomach, small intestine, large intestine and anus.
mouth
stomach
oesophagus
small intestine
pharynx
large intestine
anus
Rectum

29. The Alimentary Canal & Associated Organs
Mouth & salivary glands
Pharynx, Oesophagus
Stomach
Small intestine- duodenum & ileum
Associated organs-liver, gall bladder, pancreas
Large intestine- colon, rectum
Anus

30. Alimentary Canal & Associated Organs
mouth
stomach
oesophagus
duodenum
pharynx
colon/ large intestine
anus
salivary gland
liver
gall bladder
pancreas
jejunum
ileum
rectum

31. What we learn today. Nutrition (Definition) 5 Processes of Nutrition
Digestive Enzymes
Alimentary Canal
Alimentary Canal & Accessory Organs

32. Alimentary Canal & Associated Organs
duodenum
pharynx
gall bladder
jejunum
liver
salivary gland
ileum
oesophagus
anus
stomach
colon/ large intestine
rectum
mouth
pancreas