Functions of different organs of GIT + functions of different secretions of GIT

1. Functions of GIT
Dr. Hazrat Bilal Malakandi, PT
DPT (IPM&R,KMU), MSPT* (KMU)

2. • What is digestion?
• what is GIT? What are its parts?
• What are accessory organs of GIT?

3. Basic GIT Functions
• Primary function
– Movement of
nutrient
molecules from
the external
environment to
the internal
environment
• Done through the
processes of:

4. • Secondary
functions
– Mass balance
• Ensuring daily fluid
input and output are
equal
– Protection
• GI tract provides a
huge external surface
for pathogens to gain
entrance into the
internal environment

5. Functions of GIT
• Ingestion of food
• Digestion of food
• Secretion of digestive juices
• Absorption of water, salts, vitamins and
end products of food digestion
• Excretion of waste products
• Helps erythropoiesis by secreting intrinsic
factor needed for vit. B12 absorption.

6. Functions of tongue
1. Speech
2. Taste
3. Chewing
4. Swallowing
5. Lingual lipase
6. Cleansing of teeth
7. Moistening of lips

7. Functions of Stomach
1. Storage
• Until food is processed in stomach and
intestine
• Limit = 1- 1.5 lit
2. Mixing (with gastric secretions)
• Unless semi fluid mixture: chyme

8. 3. Absorption
–Poor absorptive area
• No villi
–Alcohol, some drugs (e.g. Aspirin)
4. Slow emptying
• At a rate suitable for digestion and
absorption in small intestine

9. Functions of Small intestine
• Two main functions
– Digestion
– Absorption
• Digestion
– 90 % of digestion occurs in small intestine
– Carbohydrates  glucose
– Proteins  Amino Acids
– Fats  Fatty acid & glycerol

10. • Absorption

11. Function of colon
• Absorption of H2o and electrolytes from
chyme (by proximal ½).
• Storage of fecal matter until it can be
expelled (by distal ½).

12. Major Functions of the Liver
1. Carbohydrate metabolism: maintains blood
sugar levels.
a. Low Sugars levels: (control- glucagon)
glycogenolysis glycogen > glucose
b. High sugars levels: (control- insulin)
glycogenesis glucose > glycogen
2. Lipid metabolism
a. Break down fats: lipolysis, beta oxidation
b. Synthesize cholesterol
c. Stores triglycerides

13. 3. Formation and secretion of bile
4. Nutrient and vitamin metabolism
5. Inactivation of various substances
6. Synthesis of plasma proteins
7. Immunity
8. Storage of Vitamins (A, B12, D, E, and
K) and iron

14. Functions of Mucus
1. Lubrication
• Coats the wall of gut (prevents actual
contact of food with gut wall)
• Low resistance for slippage
2. Protection
3. Adherent qualities
• Adherence of fecal particles
4. Resistant to digestion
5. Mild buffering properties

15. Functions of Saliva
1. Digestion
i. Salivary Amylase
 Secreted by salivary glands
ii. Lingual lipase
 Secreted by glands on the tongue
2. Articulation
3. Moistening of food
4. Mastication
5. Water regulation (thirst)
6. Swallowing
7. Keeps mouth clean
8. Neutralization of gastric acid
Relieve of heartburn

16. 10.Protection from bacteria
i. Wash away bacteria
ii. Wash away the food of bacteria
iii. Destroy bacteria

17. 11. Tooth Protection
1. By neutralizing acid
2. By affecting mineral dissociation
equilibrium by means of its
calcium phosphate content.
3. Proline-rich proteins protect the
tooth enamel and bind toxic
tannins

18. Bile functions
– Digestion of fats
• Emulsification
– Large fat particles →small fat particles
– Absorption of fats
– Excretion
• Bilirubin
– End product of hemoglobin destruction
• Excess cholesterol