Question

EXPLAIN ALL THE STEPS INVOLVE IN THE PROCESS OF DIGESTION OF HUMANS?????DEFINE HUMAN ALIMENTARY CANAL?????

Answer 1

The human digestive system consists of the gastrointestinal tract plus the accessory organs of digestion (thetongue, salivary glands, pancreas, liver, and gallbladder).[1] In this system, the process of digestion has many stages, the first of which starts in the mouth. Digestion involves the breakdown of food into smaller and smaller components, until they can be absorbed and assimilated into the body.

Chewing, in which food is mixed withsaliva begins the process of digestion. This produces a bolus which can be swallowed down the esophagus and into the stomach. Here it is mixed withgastric juice until it passes into the duodenum, where it is mixed with a number of enzymes produced by thepancreas. Saliva also contains acatalytic enzyme called amylasewhich starts to act on food in the mouth. Another digestive enzymecalled lingual lipase is secreted by some of the lingual papillae on the tongue and also from serous glands in the main salivary glands. Digestion is helped by the mastication of food by the teeth and also by the muscular actions of peristalsis andsegmentation contractions. Gastric juice in the stomach is essential for the continuation of digestion as is the production of mucus in the stomach.

Peristalsis is the rhythmic contraction of muscles that begins in the esophagus and continues along the wall of the stomach and the rest of thegastrointestinal tract. This initially results in the production of chymewhich when fully broken down in thesmall intestine is absorbed as chyleinto the lymphatic system. Most of the digestion of food takes place in the small intestine. Water and someminerals are reabsorbed back into the blood in the colon of the large intestine. The waste products of digestion (faeces) are defecated from the anus via the rectum.

Answer 2

■ MOUTH:-

♤ FLUID CALLED SALIVA SECRETED BY THE SALIVARY GLANDS.

♤ THE SALIVA CONTAINS AN ENZYME CALLED SALIVARY AMYLASE.

♤ FUNCTION :- BREAK DOWN STARCH INTO COMPLEX MOLECULE TO GIVE SUGAR.

HELP IN MOISTENS THE FOOD EASY FOR CHEWING AND SWALLOWING

■ OESOPHAGUS:-

♤ THE CANAL HAS MUSCLES THAT CONTRACT RHYTHMICALLY TO PUSH THE FOOD FORWARD & THIS MOVEMENT OF FOOD IS CALLED PERISTALTIC MOVEMENT WHICH OCCURS ALONG THE G.UT.

■ STOMACH:-

♤ GASTRIC GLANDS ARE PRESENT IN STOMACH.

♤ IT RELEASE HYDROCHLORIC ACID (HCL).

♤ FUNCTION:- KILL HARMFUL BACTERIA THAT ENTERS WITH THE FOOD.

MAKES THE MEDIUM ALKALINE.

♤ PEPSIN:- THEY ARE PROTEIN DIGESTED ENZYME.

♤ MUCUS:- PROTECTS THE INNER LINING OF THE STOMACH FROM THE ACTION OF HYDROCHLORIC ACID.

■ SMALL INTESTINE:-

♤ THE EXIT OF FOOD FROM THE STOMACH IS REGULATED BY A SPHINCTER MUSCLE.

♤ IT HELPS IN DIGESTION OF CARBOHYDRATES, PROTEINS AND FATS.

■ LIVER :- IT SECRETE BILE JUICE IN GALL BLADDER.

♤ FUNCTION:- TURN ACIDIC MEDIUM TO ALKALINE.

EMULSIFY THE ACTION OF FAT.

♤ PANCREAS:- IT SECRETE PANCREATIC JUICE IT CONTAIN ENZYME LIKE:-

♤ TRYPSIN :- HELPS IN BREAK DOWN OF PROTEINS.

♤ LIPASE :- CONVERT FAT INTO FATTY ACID AND GLYCEROL.

■ INTESTINAL JUICE:- THE WALL OF SMALL INTESTINE CONTAIN GLAND WHICH SECRETE INTESTINAL JUICE.

♤ FUNCTION :- CONVERT PROTEINS TO AMINO ACIDS.

♤ COMPLEX CARBOHYDRATES INTO GLUCOSE.

♤ FATS INRO FATTY ACIDS AND GLYCEROL.

■ VILLI:- THE INNER LINING OF THE SMALL INTESTINE HAS NUMEROUS FINGER LIKE PROJECTIONS CALLED VILLI.

♤ FUNCTION:- INCREASE THE SURFACE AREA FOR ABSORPTION.

THEY ARE RICHLY SUPPLIED WITH BLOOD VESSELS WHICH TAKE THE ABSORBED FOOD TO EACH AND EVERY CELL OF THE BODY

■ LARGE INTESTINE:-

THE EXIT OF WASTE MATERIAL FROM THE BODY IS REGULATED BY THE ANAL SPHINCTER.