Digestive System Explanation in English | GI System | How Many Parts Of Digestive System | Digestive System And Function | Digestive System Theory |
Digestive System Explanation in English

how many parts of digestive system | digestive system and function
Digestive System: The digestive tract (G.I. tract) comprises the following structures:
The Mouth Cavity: Teeth, hard and soft palate, Tongue, salivary glands (one pair each of parotid, submaxillary and sublingual).
Function: The food which is taken into the mouth is chewed with teeth and mixed with saliva, secretions of salivary glands to render it into a state suitable for swallowing.
Pharynx: Acts only for food passage
Oesophagus: -do-
Stomach (GI System)




A muscular bag just below the diaphragm at the end of the Oesophagus retains food for several hours. It has got 3 segments fundus, body & Pylorus.
Function: Digestion of protein & fat by gastric juice Pepsin (in the presence of HCl) and Lipase respectively, Gastric rennin coagulates milk. The pH of the stomach is in the range of 0.9 to 1.5.
Small Intestine: Duodenum, Jejunum lleum.
Function: Final step of digestion of food with pancreatic juice and its own secretion succus entericus. Bile helps in fat absorption.
Large Intestine: Caecum Ascending Colon Transverse Colon, Descending Colon, Sigmoid Colon, Rectum, Anus.
Function: mainly water absorption and excretion of waste products faeces or stool.
The function of the entire system is aided by secretions from the largest gland liver (bile) and mixed gland pancreas (pancreatic juice).
What Is Digestion?
Digestion is a process where complex food molecules are broken down into simple forms, which can be absorbed and used by the body.
What Are Enzymes?
Enzymes are soluble organic catalysts manufactured by living cells.
What Does Gastric Juice Contain?
Gastric juice contains :
- Pepsin (acts on protein to peptones in presence of HCl)
- Rennin(coagulates milk)
- Small amount of gastric lipase (fat splitting enzyme)
What Is The Liver?




- Liver is the largest gland in the body.
- Liver is the headquarters of metabolism
- Liver is the part of the digestive system
Where Is Liver Situated?
It is situated in the upper right region of the abdominal cavity beneath the diaphragm.
What Are The Functions Of Liver?
The functions of the liver are :
- Production of Bile.
- Storage of Glycogen.
- Formation of Urea.
- Storage of B12 and iron.
- Production of Heparin (anticoagulant)
- And also prothrombin, fibrinogen to help to clot.
- Detoxification of toxic substances through the metabolic process.
What Are The Functions Of Pancreas?
With its exocrine secretions pouring into Duodenum:
- Trypsin acts on proteins.
- Amylase acts on carbohydrates.
- Lipase acts on fats.
Note: remember endocrine pancreas secretes insulin a hormone that regulates blood sugar.
How Carbohydrates, Proteins And Fats Are absorbed In The Body?
They are absorbed in the body through intestinal villi in the form of:
- Amino acids(from protein).
- Fatty acids and glycerol(from fat)
- Glucose (from Carbohydrate)
What Is Metabolism?
Metabolism involves the biochemical processes through which complex substances are broken down with liberation of energy(catabolism) and building up complex substances from simple ones in the formation of tissue protein (anabolism).
What Is Peristalsis?
An involuntary wave of muscular contraction followed by dilatation starting from the Oesophagus in presence of food affects the easy forward passage of food.
What Is Sphincter?
A specialized ring of muscles surrounds an orifice allowing the substance to pass in the forward direction only.
What Is Calorie?
A unit of heat equal to the amount of heat required to raise the temperature of 1 gm of water through 1°C.
Vitamins:
Group of substances essential for body growth. They do not produce calories but act as catalysts. We require small amounts. They can’t be synthesized in the body but are available in the food we take.
They are of two types. The water-soluble group includes vitamin B complex and vitamin C. The fat-soluble group includes vitamin A, D, E, K.
Vitamin deficiency cause diseases.
Minerals:
These are inorganic substances in the diet, required in small amounts, essential for life. To name major minerals calcium, magnesium, sodium, potassium, phosphorus, sulphur etc.
Common Diseases Of G. I. Tract
1) Gastritis
2) Ulcers
3) Dysentery
4) Diarrhoea
5) Dyspepsia
6) Flatulence
7) Appendicitis
8) Jaundice
9) Hepatitis
10) Cirrhosis of the liver.
Digestive System Theory
FAQs
Q. What is calories?
A. A unit of heat equal to the amount of heat required to raise the temperature of 1 gm of water through 1°C.
Q. What are enzymes?
A. Enzymes are soluble organic catalysts manufactured by living cells.
Q. What is Metabolism?
A. Metabolism involves the biochemical processes through which complex substances are broken down with liberation of energy(catabolism) and building up complex substances from simple ones in the formation of tissue protein (anabolism).
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