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Student number: 201200489 Surname: ndHLOVu Initial: Z.m Subject: prOfeSSIOnaL StudIeS3a The document discusses the digestive system and the process of digestion. It describes the mechanical and chemical breakdown of food and the roles of the mouth, esophagus, stomach, small intestine, large intestine and accessory organs like the liver, gallbladder and pancreas. Key phases of digestion include ingestion, digestion, absorption and excretion. The document also outlines the movement of food through the digestive tract and the structures that aid in digestion.
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- 1. STUDENT INFORMATION Student number: 201200489 Surname:ndHLOVu InItIaL: Z.m Subject: prOfeSSIOnaL StudIeS3a
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- 3. DIGESTION The chemical breakdownof complex biological molecules into their component parts. Lipids to fatty acids Proteins to individual amino acids Carbohydrates into simple sugars
- 4. DIGESTION Mechanical Changes the physicalform of food Chew Tear Grind Mash Mix
- 5. DIGESTION Chemical Changes the chemicalcomposition of food with the aid of digestive enzymes Protein Carbohydrate Lipid Digestive enzymes are special proteins that help break up large molecules of food into very tiny molecules that can be absorbed and used by the cells in the form of nutrition.
- 6. FUNCTION Produces various chemicals tobreak down the food. Filters out harmful substances. Gets rid of solid wastes.
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- 8. THE DIGESTIVE TRACT Along muscular tube with many sections and areas. Begins with the mouth and ends with the anus.
- 9. THE DIGESTIVE TRACT Partsof the Digestive Tract Mouth Pharynx Esophagus Stomach Small Intestine Large Intestine Anus
- 10. ACCESSORY PARTS Organs that arenot in the digestive tract but helps in the digestion Teeth Tongue Salivary glands Liver Gall bladder Pancreas
- 11. MOUTH Functions: Food enters inthe mouth or oral cavity Tasting Mechanical breakdown of food Secretion of salivary glands (salivary amylase)
- 12. MOUTH Structures in themouth that aids digestion: Teeth – cut, tear, crush and grind food. Salivary glands – produce and secrete saliva into the oral cavity. Parotid (beneath the cheeks) Submaxillary (below the jaw bone) Sublingual (below the tongue) – saliva moistens the food and contains enzymes (ptyalin or salivary amylase) that begins digestion of starch into smaller polysaccharides.
- 13. MOUTH Tongue Mixes and rollsfood into tiny mashed up bits (Bolus) Pushes the bolus toward the pharynx and into the esophagus when swallowing.
- 14. ANATOMY OF THEMOUTH AND THROAT
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- 16. MECHANISM OF SWALLOWING Swallowing isa coordinated activity of the tongue, soft palate, pharynx and esophagus. Phases Food is pushed into the pharynx by the tongue. (voluntary) Tongue blocks the mouth Soft palate closes off the nose Larynx (Adam’s Apple) rises so the Epiglottis (a flap of tissue) can close the opening of the trachea.
- 18. ESOPHAGUS A straight musculartube that is about 10 inches (25 cm) long which connects the mouth with the stomach Food takes about 4 to 8 seconds as it passes through to the stomach. Its walls contain smooth muscles that contracts in wavy motion . Cardiac Sphincter (ring-like valve) relaxes to allow food into the stomach.
- 19. STOMACH J-shaped muscular sac Hasinner folds (rugae) that increases the surface area of the stomach. Churns and grinds together the bolus into smaller pieces. Food is mixed with gastric juices (hydrochloric acid and enzymes) secreted by the stomach walls. HCL helps break down food and kills bacteria that came along with the food.
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- 21. STOMACH Pepsin – majorenzyme; converts proteins into peptides in the presence of HCL. Mucus – lubricates food and protects the gastric lining from strong digestive juices. Converts the bolus into a liquid (chyme) after 4 hrs of mechanical and chemical digestion Chyme passes through the pyloric sphincter into the small intestine.
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- 23. ACCESSORY ORGANS Produce or storeenzymes that helps in digestion. Liver Largest gland of the body Stores vitamins A,D,E,K Stores sugar and glycogen Produces bile (watery, greenish substance) Secretes bile to the gall bladder via the hepatic duct and cystic duct.
- 24. ACCESSORY ORGANS Gall bladder Stores bilein between meals Secretes bile to the duodenum through the bile duct during mealtime. Bile contains bile salts, pigments, cholesterol and phospholipids. Bile is an emulsifier NOT an enzyme. Emulsifier – dissolves fat into the watery contents of the intestine.
- 25. ACCESSORY ORGANS Pancreas Produces ajuice that contains enzymes (amylase and insulin) to break down carbohydrates, fats and protein. Secretes the juice into the duodenum through the pancreatic duct.
- 26. SMALL INTESTINE Long (20ft), coiled tube beneath the stomach. Has three parts: Duodenum – upper part; about 10 in; connected to the stomach. – where the digestive juices from the pancreas and the liver combine with chyme making it thin and watery. Jejunum – about 8 ft Ileum – about 12 ft
- 27. SMALL INTESTINE Site ofgreatest amount of digestion and absorption
- 28. SMALL INTESTINE Takes about4 – 8 hrs to complete its journey. Mucosa (inner wall) – secretes several enzymes that acts on the food. Where the pancreatic enzymes are emptied into. Digested nutrients are absorbed through intestinal walls. Absorbed materials cross the mucosa into the blood then other parts of the body for storage or further chemical change.
- 29. SMALL INTESTINE Has foldedinner walls covered with fingerlike projections (villi; sing. – villus) Each villus has tinier projections called microvilli that absorbs digested food. Villi and microvilli increases the surface area of the small intestine for greater absorption. Peristalsis moves the undigested food to the large intestine.
- 30. MOVEMENT IN SMALL INTESTINE: Mixing:Segmental contraction that occurs in small intestine Secretion: Lubricate, liquefy, digest Digestion: Mechanical and chemical Absorption: Movement from tract into circulation or lymph Elimination: Waste products removed from body
- 31. LARGE INTESTINE A.k.a. Colon largerdiameter, but shorter (5 ft) Water is absorbed from the undigested food making the waste harder until it becomes solid. Waste stays for 10 – 12 hours.
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- 33. LARGE INTESTINE Waste ispushed into the expanded portion (rectum) of the large intestine. Solid waste stays in the rectum until it is excreted through the anus as feces. Appendix hangs on the right side of the large intestine.
- 34. EXCRETION OF URINE Kidney Ureter– a tube that transports urine to the urinary bladder. Urinary Bladder – a sac of tissue that has the ability to expand as it fills with urine. Urethra – a tube at the bottom of the bladder where urine passes out of the body.
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- 36. THE END OFTHE PROCESS Solid waste is then stored in the rectum until it is excreted via the anus.
- 37. REFERENCES Goyal, t. ,(2010). Life sciences digestive system. Slide share. cook, J.L (2006). Life sciences digestive system. slide share. All the pictures that I have been used are taken from Google image