summarized description of human digestive system

1. Digestive System
By: Virginia
Ravindu
Sashini
Siumi
Yashodara

2. 1. Introduction
2. DefinitionofDigestion
3. ImportanceofDigestion
4. FunctionsofDigestion
5. Diseases
6. Conclusion

3. Digestion refers to the breakdown of
food into smaller components that can
be absorbed into the bloodstream.

5. The Digestive System
 Different biological processes take place in the human body.
 Digestion is one of the main processes among them.
 Energy is required for various biological functions & Food is
considered as the source of energy.
 These food contain,
Nutrients
Proteins
Carbohydrates
lipids
 The process by which the complex organic compounds are
converted into simple compounds so as to be absorbed by the
human body is called digestion of food.

6. • Digestion of food
Mechanical Chemical
Breakdown of
food into smaller
pieces by
chewing
Starch is
converted into
maltose by
salivary amylase.
Starch salivary amylase Maltose

7.  Mouth
 Bite, chew and swallow
 Pharynx &Oesophagus
 Transport
 Stomach
 Bolus is broken down into a chyme
 Small intestine
 Absorption
 Large intestine
 Absorption of vitamins (B and K)
 Rectum and anus
 Defaecation
Functions of digestion

8. 1. Digestion in the Buccal Cavity
2. Digestion in the Stomach
3. Digestion in the Small Intestine
4. End products of Digestion
Stages of Digestion

9. • 1. Digestion in the Buccal Cavity
• Food enters to the digestive system through buccal cavity.
• food is subjected to physical digestion due to the chewing.
• Saliva in the mouth cavity digest starch to maltose.
 Starch salivary amylase Maltose
• saliva in the mouth cavity performs the following tasks,
– Helps to stick food particles to form a food bolus
– Makes food substances wet and slippery
• Tongue is important to make the food bolus and to identify a variety of tastes
present in food.

10. Epiglottis
 Common chamber for both digestive and respiratory systems.
 Situated immediately above the pharynx
 Prevents entry of food to the trachea.
Oesophagus /food pipe
 Runs from pharynx to stomach
 Consist of longitudinal and circular muscles
 Food is moved towards the stomach through peristaltic movements

11. Digestion in
stomach

12. • Stomach
 Lining of the stomach produce HCL(hydrochloric acid) and pepsin to
breakdown proteins to polypeptides.
 Renin - coagulates milk in infants
 bolus is converted into ‘Chyme’ in the stomach.
 It contains,
 Partially digested proteins
 Digested and undigested carbohydrates, lipids, water, minerals & vitamins.
 When the stomach is empty it contracts and causes a pain which signals
hunger.
 Food in the stomach is send to the small intestine through pyloric splinter.

13. Digestion in the small
intestine

14. 3. Digestion in the Small Intestine
 The small intestine consist of 3 parts,
Duodenum
Jejinum
Ileum
Duodenum is a C – shaped tubular structure.
Bile and pancreatic duct open to duodenum.
It’s produced in liver and stored in the gall bladder.
Conversion insoluble lipids to soluble stage in water is known as ‘Emulsification’.
Following table depicts the digestion in the small intestine.
organ enzyme substrate End product
pancreas Trypsin
Amylase
Lypase
Protein
Starch
Lipids
Polypeptides
Maltose
Fatty acids & glycerol
Small intestine Maltase
Sucrase
Lactase
Peptidase
Maltose
Sucrose
Lactose
polypeptides
Glucose
Glucose+Fructose
Glucose+Galactose
Amino acids

15. 4. End products of Digestion
•Carbohydrates monosaccharides
•Proteins amino acids
•Lipids fatty acids + glycerol

16. • What happen to the end products?
• The digestive end products are absorbed into the blood capillaries of the small
projections known by the name villi.
• Fatty acids and glycerol are absorbed into lacteals.
• When high amount of glucose is present in blood converted into glycogen
• When glucose concentration is decreased glucose breaks down to form glucose
• The undigested food is then transferred to the large intestine.

17. Process in the large intestine

18. •By the time the gut have reached the end of the small intestine, most
of the digested food, water has been absorbed.
•The waste materials consists mainly of,
–Cellulose (fibre)
–Water
–Dead and living bacteria
–Cells lost from the lining of the gut.
•First part of the large intestine, called as colon, is to absorb most of
the remaining water from the contents, leaving a semi-solid waste
material called Faeces.
•This is stored in the rectum, until expelled out of the body through
the anus.

19. Disease Symptoms Reasons Prevention
Gastritis Regurgitation of acid to
mouth.
Burning feeling and pain
in stomach.
Skipping of meals
Mental stress
Consumption of acidic
and spicy food
By following good health
diets.
Constipation Difficulty in defeacation Postponing of
defeacation
Not taking required
volume of water
By avoiding the
mentioned bad habits
Typhoid Pain in arms and legs
Headache
Fever
constipation
Leaving out food in the
air
Intake of pool water
during swimming
Get a vaccine for typhoid.
Destroying places where
flies breed.
Diarrhoea Release of faecal matter
in liquid matter.
Infected with a virus,
bacteria or a parasite
Consumption of more
water.
Wash hands well with a
soap after using the
bathroom
Diseases and disorders related with digestive system

21. Any Questions?