DIGESTION

The breakdown of complex food intoi l f i ll d Di isimplest form is called Digestion.

Enzymatic hydrolysis of complex food intoits simplest form at a specific pH value isp p pcalled Digestion.

TYPES Intracellular Digestion

Intercellular Digestion

Mechanical Digestion

Chemical DigestionC e ca gest o

STRUCTUREBUCCO‐PHARYNGEAL CAVITY

GASTRO‐INTESTINAL TRACT OR  ALIMENTARY CANAL

ANATOMY OF ALIMENTARY CANAL SerosaMuscularisSub‐MucosaMucosao Villio Blood capillarieso Lacteoleso GlandsL i  P io Lamina Propria

ACCESSORY DIGESTIVE ORGANS

Salivary Glands: TheySalivary Glands: Theyare exocrinal glands foundwithin the buccal cavity atwithin the buccal cavity atdifferent sites. They arepaired structurespaired structures.

They are of Three types namely:

a)Parotid glands: found just below the ear lobe orithi th h kwithin the cheek.

b)S b dib l /S b ill l d f db)Sub‐mandibular/Sub‐maxillary glands: foundbelow the lower jaw.

c)Sub‐lingual glands: found below the tongue.

LIVER & PANCREAS

LIVER: It is the largest exocrine gland foundg gin man. It is five lobed It has four completelobes and one incomplete lobe. They extendp yhepatic ducts. Just behind the third lobe ithas Gall bladder which extends cystic duct.yBoth of them fuse to form Bile duct.It secretes Bile; helps in digestion of fats.It secretes Bile; helps in digestion of fats.

PANCREAS: It is an irregular multilobularyellow coloured dual gland found withinyellow coloured dual gland found withinthe loop of duodenum. It has exocrinalunits called Acini which secrete pancreaticunits called Acini, which secrete pancreaticjuice helps in digestion of carbohydrates,proteins and lipids It ha endocrinal unitsproteins and lipids. It ha endocrinal unitscalled Islets of langerhans which secreteGlucagon Insulin and somatostatin whichGlucagon, Insulin and somatostatin whichregulate carbohydrate metabolism.

PHYSIOLOGY OF DIGESTIONDigestion in Bucco‐pharyngeal cavity:IngestionRetentionMasticationInsalivationPartial hydrolysisFormation of bolusSwallowingP i li iPeristalisis

Digestion in Stomach:Digestion in Stomach:Role of HClRole of PepsinRole of ReninRole of ReninChymeRole of Pyloric Sphinctors

Digestion in Small intestine:gDigestion of ProteinsoRole of TrypsinoRole of TrypsinoRole of Chymo‐trypsinoRole of Carboxy‐peptidaseoRole of Amino‐peptidesp poRole of Erepsin

Digestion of CarbohydratesDigestion of Carbohydrateso Role of Amylopsino Role of MaltaseRole of Sucrase/In ertaseo Role of Sucrase/Invertase

o Role of Lactase

Digestion of Lipids:o Emulsificationo Emulsificationo Role of Steapsino Role of Intestinal Lipase

Chyle:o Role of Villio Role of Villio Role of Colono Role of Rectum

ROLE OF APPENDIX CicumVermiform appendixVermiform appendixRole of appendix

ABSORPTION Definition Structure of villus Structure of villus Mechanism of absorption

DIGESTIVE DISORDERSJaundice: The liver is affected, skin and eyesturn yellow due to the deposit of biley ppigments.

Vomiting: It is the ejection of stomachcontents through the mouth This reflexcontents through the mouth. This reflexaction is controlled by the vomit centre inthe medulla A feeling of nausea precedesthe medulla. A feeling of nausea precedesvomiting.

Diarrhoea: The abnormal frequency of bowelmovement and increased liquidity of the facealmovement and increased liquidity of the facealdischarge is known as diarrhoea. It reduces theabsorption of food.pConstipation: In constipation, the faeces arerelated within the rectum as the bowelrelated within the rectum as the bowelmovements occur irregularly.Indigestion: In this condition, the food is notIndigestion: In this condition, the food is notproperly digested leading to a feeling offullness. The causes of indigestion areginadequate enzyme secretion, anxiety, foodpoisoning, over eating and spicy food.