Question

mention various steps involved in the process of digestion in humans

Answer 1

■ 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.

Answer 2

$\textbf{Alimentary Canal }$:

The digestive system from Oesophagus to the anus is called alimentary canal. It is about 9 metre long. It is also called food tube.

It constitutes the organs namely :

Buccal cavity, Oesophagus, Stomach, Small intestine, Large intestine, Rectum, Anus.

$\textbf{Role of mouth }$:

Humans take in food through the mouth. It is the uppermost part of alimentary canal which is bounded by lips and cheeks, and contains tongue and slaivary gland. The food taken in is chewed or groinded by teeth at the same time in the salivary glands, saliva starts to secrete which contains enzymes( $\textbf{Salivary Amylase }$ )that breaks search into sugar.

Now the tongue helps in mixing this saliva with food, it also gives taste of food also it helps in swallowing the food.

$\textbf{Role of oesophagus}$ :

It is tubular part of alimentary canal about 25cm long. It is also the narrowest part of alimentary canal. It is hollow which allows the passage of food from Buccal cavity to the stomach. During which food gets mixed with various digestive juices.

$\textbf{Role of Stomach }$

It is J-shaped bag like structure made of muscle. Here gastric glance are present which secret mucus, HCL and digestive enzymes. The function of mucus is to protect stomach lining from the action of enzymes and acid. HCL kills bacteria present in food, making the food acidic; so that enzymes can act on it. Here food stays for 4-5 hours.

$\textbf{Role of Large intestine, Rectum and Anus}$:

It is about 1.5 m long organ Food from small intestine moves here. Here the most of water and salt be removed from the water by the absorbtion. This intestine allow the passage of faecal matter through the anus.