HUMAN DIGESTIVE SYSTEM

2.  The breakdown of large insoluble food molecules into
small soluble molecules to be absorbed into the body
cell.
Or
Changes food you eat into nutrients that your cells
can use.

3. Main Parts Are:- Accessory Parts Are:-
Mouth Liver
Esophagus Pancreas
Stomach Gallbladder
Small Intestine Salivary Gland
Large Intestine

4. Ingestion:- Taking In Of Food Into The Body
Digestion:- Breaking Down Of Food Into Simpler
Substances.
Absorption:-Diffusion Of Food From Small Intestine Into
Blood.
Assimilation:- Using Digested Nutrients To Make New
Material.
Egestion:-Removal Of Undigested Waste Material Out Of
The Body.

5.  Mechanical (physical)
 Chew
 Tear
 Grind
 Mash
 Mix
 Chemical
 Enzymatic reactions to improve digestion of
 Carbohydrates
 Proteins
 Lipids

6.  Teeth mechanically break down food into small pieces.
 Tongue mixes food with saliva (contains amylase, which
helps break down starch).
 Saliva Convert Starch into Maltose.

7. Approximately 10” long
 Functions include:
1. Secrete mucus
2. Moves food from the throat to the stomach using
muscle movement called peristalsis
3. No Digestion Takes Place
4. Food Stays In The Esophagus For 10 Sec.

8.  J-shaped muscular bag that stores the food you eat, breaks
it down into tiny pieces.
 Mixes food with digestive juices that contain enzymes to
break down proteins and lipids.
 Acid in the stomach kills bacteria.
 Food Stays in The Stomach for 2 to 6 hours.
 There Is No Digestion Of Carbohydrates And Fats In
The Stomach.

9.  Small intestines is roughly 7 meters long.
 It is subdivided into duodenum ,jejunum,ileum.
 Lining of intestine walls as finger-like projections called
villi, to increase surface area.
 The villi are covered in microvilli which further increases
surface area for absorption.
 In the Small intestine , chyme stimulates
1 Pancreas to secrete pancreatic juice.
2 Gall Bladder to Secrete Bile.
3 Intestinal Glands to secrete intestinal juice

10.  All three juices are secreted are alkaline.
 The Digestion of Food in The Small Intestine Are As
Follows :-
Digestion of starch:
Starch To Maltose
Maltose To Glucose
Digestion of small protein molecules
Protein molecules To amino acids
Digestion of fats:
Fat To Fatty acids and glycerol

11.  Absorbs:
 80% ingested water
 Vitamins
 Minerals
 Carbohydrates
 Proteins
 Lipids
Food Stays in The Small
Intestine For About 5 Hours.

13.  Large inverted U shaped tube.
 No digestion takes place here
 Absorbs water and minerals salts
 Stores the faeces (dead cells, mucus, germs,
undigested food.
 About 94% of the total amount of water passing
through the alimentary canal is absorbed by the small
intestine! The large intestine absorbs most of the
remaining 6% of water

15. These organs do not digest food but aid in digestion
 Gall bladder
 Pancreas
 Liver

16. • It is the largest organ in the mammalian body.
• It secretes bile which is stored in the gall bladder.
 Bile breaks down fats into tiny droplets through
 emulsification.
 Roles:
• Regulates sugar/glucose
• Breaks down excess RBC
• Storage of blood
• Detoxification
• Generation of heat

17. • It is an endocrine gland because it secretes
Insulin hormone - converts excess glucose
into glycogen for
 storage.
• It is also an exocrine gland because it secretes
 pancreatic juice in the duodenum
 - pancreatic juice contains lipase, trypsin and
 pancreatic amylase for digestion of lipids,
 proteins and starch.

18.  Temporarily stores bile (smelly green substance)
secreted by liver.
 Secretes bile in the presence of chyme.
 Bile breaks up large fat droplets into very small fat
droplets to increase surface area for lipase action
(Emulsification) Bile emulsifies fats
 *Bile is not an enzyme, so it is not affected by
temperature