Fuctions of GIT

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 Speech Taste Chewing Swallowing Lingual lipase Cleansing of teeth Moistening of lips

7. Functions of Stomach Storage Until food is processed in stomach and intestine Limit = 1- 1.5 lit 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 Carbohydrate metabolism : maintains blood sugar levels. a. Low Sugars levels: (control- glucagon) glycogenolysis glycogen > glucose b. High sugars levels: (control- insulin) glycogenesis glucose > glycogen 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 Lubrication Coats the wall of gut (prevents actual contact of food with gut wall) Low resistance for slippage Protection Adherent qualities Adherence of fecal particles Resistant to digestion Mild buffering properties

15. Functions of Saliva Digestion Salivary Amylase Secreted by salivary glands Lingual lipase Secreted by glands on the tongue Articulation Moistening of food Mastication Water regulation (thirst) Swallowing Keeps mouth clean Neutralization of gastric acid Relieve of heartburn

16. Protection from bacteria Wash away bacteria Wash away the food of bacteria Destroy bacteria

17. 11. Tooth Protection By neutralizing acid By affecting mineral dissociation equilibrium by means of its calcium phosphate content. 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