The document summarizes the human digestive system in 8 steps: 1) Mouth and esophagus where food is ingested and moved to the stomach through peristalsis. 2) Stomach which secretes gastric juices and enzymes like pepsin to break down proteins. 3) Small intestine which receives secretions from the liver and pancreas that further digest food, and intestinal villi which absorb the digested nutrients. 4) Large intestine where water is absorbed and remaining waste is sent to the rectum. 5) Rectum and anus where undigested waste is stored and expelled.

1. HUMAN DIGESTIVE SYSTEMMADE BY: ANKIT VYASCLASS: X BROLL NO.: 35

2. HUMAN DIGESTIVE SYSTEM

3. DIGESTION PROCESS1. Mouth and buccal cavity Mouth open into buccal cavity. It has muscular tongue which helps in ingestion of food. It has two jaws with four types of teeths, in buccal cavity. Saliva contain an enzyme salivary amylass or ptyalin which convert starch into sugar. starch------------------------->sugar

4. 2. OESOPHAGUS Buccal cavity open into long tabular muscular structure through funnel shaped pharynx. No digestion occur in it. The lining of alimentary canal has muscles that contract rythmically in order to push the food forward. This movement is known as PERISTALTIC movement, it occurs all along the gut.

5. 3. STOMACH Food passes to j-shaped stomach. It has branched tubular glands present in it’s wall which secrets gastric juices containing hydrochloric acid(HCL) , mucus, protein digestive enzyme (pepsin) and gastric lipase.

6. 3.1 FUNCTION OF HCLIt makes the medium acidic for proper functioning of pepsin. Pepsin get activated by HCL.HCL stops the functioning of salivary amylass.It kills the germs or bacteria to disinfect food.

7. 3.2 FUNCTION OF MUCUSMucus protect the inner lining of stomach from the acid and enzyme.3.3 FUNCTION OF ENZYMEIn acidic medium pepsin act on protein and convert it in simpler forms like peptones and pepteosis.Gastric lipase convert a little amount of fat into fatty acids and glycerols.

8. 4. SPHINCTER MUSCLES Sphincter muscles regulate the passage of food from stomach to small intestine. These are present at the base of stomach and ir regulated by contraction and expansion.

9. 5. SMALL INTESTINEIt is the longest part of the alimentary canal. It’s proximal or the interior part receives the secretions from the liver and the pancreas.

10. 5.1 LIVERIt is the largest gland which secrets bile juice which is stored in gall bladder. Further secretions of the bile juice passes from gall bladder to small intestine. Bile juice emulsify the fat (convert large globule of fat to small globule of fat) to facilitate the enzyme action efficiently.

11. 5.2 PANCREASIt is also a digestive gland which secrets pancreatic juices which contain trypsin for digesting proteins and lypase for breaking down emulsified fat.

12. 6. INTESTINAL GLANDSThese glands are present in the wall of small intestine which secrets intestinal juice or succus entericus. It contain number of enzymes which complete the digestion of food. Thus, the small intestine is the site of complete digestion of food where proteins are finally converted into amino acids, complex carbohydrates into glucose and fats into fatty acids and glycerols. The posterior or the distal part take part in the absorption of digested food. For this the inner lining of small intestine has numerous finger like projection called villi, which are rich in blood vessels thus increase the surface area for absorption of digested food. The blood vessels absorbs the digested food and passes it to each and part where it is utilize to produce the energy (assimilation), building up of new tissues and repair of old tissues.

13. 7. LARGE INTESTINEUndigested food along with the large amount of water passes to large intestine. Here extra amount of water is absorbed by the wall of large intestine and remaining food passes to rectum.

14. 8. RECTUM & ANUSUndigested food is collected as faces in the rectum. Rectal wall also absorbs some water from it and faccal matter is egested out from the anus. It is regulated by sphincter muscles.

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