human digestive system

HUMAN DIGESTIVE SYSTEM

MADE BY: ANKIT VYASCLASS: X B

ROLL NO.: 35

HUMAN DIGESTIVE SYSTEM

1. 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

DIGESTION PROCESS

THE MAJOR SALIVARY GLANDS

HUMAN PERMANENT TEETH

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.

PERISTALTIC MOVEMENT

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.

STRUCTURE OF STOMACH

3.1 FUNCTION OF HCL• It 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.

3.2 FUNCTION OF MUCUS• Mucus protect the inner lining of stomach from the acid and

enzyme.

3.3 FUNCTION OF ENZYME• In 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.

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.

5. SMALL INTESTINE

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

STRUCTURE OF SMALL INTESTINE

5.1 LIVER• It 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.

STRUCTURE OF LIVER

5.2 PANCREAS• It is also a digestive gland which secrets pancreatic

juices which contain trypsin for digesting proteins and lypase for breaking down emulsified fat.

STRUCTURE OF PANCREAS

6. INTESTINAL GLANDS• These 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.

7. LARGE INTESTINE• Undigested 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.

STRUCTURE OF LARGE INTESTINE

8. RECTUM & ANUS• Undigested 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.