1. How do saliva, pancreas and liver
help in the digestion of food in man.
Draw a diagram of
digestive system to show
the position of pancreas
and liver.

2. Saliva
• Saliva is produced by glands.
• These are called salivary glands
• There are of 3 kinds and are in 3 pairs

3. Sublingual gland
• They are found below the tongue

4. Ingredients in saliva
• 1/ water and mucous
• 2/ NaHCO3 and salts
• 3/amylase (ptyalin) which digests CHO

5. 1/ water and mucous
• Together they form slimy liquid which
moistens and lubricates the food.
• This is how food can be chewed efficiently and
can pass down food pipe easily.

7. 2/ NaHCO3 and salts
• They are slightly antiseptic but theirmain
function is to stabilize pH of food.

8. 3/amylase (ptyalin) which digests CHO
• It digests starch and glycogen to maltose.

9. pancreas
• It is a large gland.
• Its exocrine tissue secretes a juice.

11. Glands
• Glands in the human body are classified as
exocrine or endocrine. The secretions of
exocrine glands are released through ducts
onto an organ's surface, while those of
endocrine glands are released directly into the
blood.
•

12. Pancreatic enzymes and other
ingredients
• Amylase
• Lipase
• Trypsin
other ingredients
NaHCO3

13. • Pancreatic juice flows from pancreatic duct
into duodenum.
• Enzymes in pancreatic juice digest CHO,f ats
and proteins.

14. Amylase
• Also called amylopsin .
• It digests starch in to maltose.

15. starch
• It is the most common carbohydrate in the
human diet and is contained in large amounts
in such staple foods as potatoes, wheat, maize
(corn), rice.

16. Lipase
• It digests fat.
• It hydrolyses a small percentage of fats into
fatty acids and glycerol.

17. Glycerol
• It is a colorless, odorless, viscous liquid that is
widely used in pharmaceutical formulations.
Glycerol has three hydroxyl groups that are
responsible for its solubility in water and its
hygroscopic nature. The glycerol backbone is
central to all lipids known as triglycerides.
Glycerol is sweet-tasting and of low toxicity.

18. Trypsin
• IT is secreted as inactive form called
trypsinogen.
• It is activated by enterokinase.
• IT splits proteins in to peptones and
polypeptides.

19. Enterokinase.
• Is secreted by lining of duodenum

20. NaHCO3
• It partly neutralizes chyme coming from
stomach.
• It is necessary because enzymes of pancreas
do not work well in acid conditions.

21. Liver
• It secretes bile.
• Bile is temporarily stored in gallbladder.
• Bile is released in to duodenum through bile duct.
• Bile is green in colour and is a watery fluid.
• It has no enzymes.
• Bile’s green colour is due to bile pigments.
• Bile also has bile salts.

23. How are bile pigments formed
• They are formed by breakdown of Haemoglobin
in the liver.
• If bile pigments cant leave digestive tract they get
accumulated in blood and cause
jaundice.
Gallstones can stop bile pigments from leaving
the digestive tract / block release of bile.

24. Bile salts
• They act on fats and emulsify them.
• Emulsification means break them up in to
small globules which are then easily digested
by lipase.

25. Gallstones
• When cholesterol precipitates in gall bladder ,
it forms gall stones.
• Cholesterol is produced by liver.

26. Functions of liver
• Liver converts toxic (dangerous to human
health)substances to less toxic compounds.
• Ammonia is converted to urea.
• Urea leaves body through kidneys.