Life Processes Part-03 (English)

 Nutrition in Animals

 Animals depend on other organisms for their food.  They get their food from plants or other animals.  Animals cannot make their own food.  They depend on others, so animals are hostile.

 In general, animals obtain their food directly or indirectly from plants.  On the basis of food, animals are divided into 3 classes -

 (i) Herbivores

 (ii) Carnivores

 (iii) Omnivores

 (i) Herbivores - Those animals who get their food only from plants are called vegetarian.  These animals only eat plants.

 Such as goat, cow, buffalo, deer, elephant, rabbit etc.

 (ii) Carnivores - Animals that call only other animals as their food are called carnivores.

 Such as - lion, tiger, vulture, snake etc.

 (iii) Omnivores - Animals that eat both animals or plants as their food are called omnivores.

 Such as human, dog, bear, crow etc.

 Different stages of nutrition process in animals-

 1- Ingestion- The process of ingesting food inside the body is called ingestion.

 2- Digestion- In this, the food of large insoluble pieces is broken into small soluble pieces.

 3- Absorption- The process in which digested food reaches the blood from the intestine walls is called absorption.

 4- Disorganization- The use of absorbed food by the cells of the body is called disorganization.

 5- Exfoliation- The process of taking out undigested food from the body is called exfoliation.

 Nutrition in Amoeba

 The amoeba is a unicellular organism, in which all functions are carried out in a single cell.  Its body shape is irregular.  When it comes in contact with a food, it produces a finger-like structure from its cell, which is called Kootapada.  It surrounds the food and forms food vacuole.  This is followed by deposition of enzymes in this food vacuole and digestion of food.  The digested food is absorbed into this cell, and the undigested food is released out of the cell by this food vacuole.

 Nutrition in Humans

 Nutrition in humans is done by the human digestive system.  The digestive system of man is made up of alimentary canal and its related glands.  The human digestive system consists of various organs such as the mouth, esophagus, stomach, small intestine, large intestine.  Apart from this, there are some glands like- gastric, salivary gland, liver.


 In humans, ingestion of food is done through the mouth.  And from here the digestion of food also starts.  Our teeth in the mouth act as breaking food into small pieces.  Amylase enzyme is added to our saliva by the salivary glands present in the mouth.  This enzyme breaks down the starch present in food into sugars.  After this, the food mixed with saliva reaches esophagus through esophagus.  The glands present in the stomach wall secrete gastric juice.  Containing hydrochloric acid, pepsin enzyme, and mucosa.  Due to hydrochloric acid, food enters the acidic medium in the stomach.  In acidic medium, pepsin starts digestion of proteins present in food.  The mucosa forms a covering on the wall of the stomach, which can protect the walls of the stomach through acidic medium.

 The partially digested food in the stomach then enters the small intestine.  The small intestine is the longest section of the alimentary canal that can range in length from 5 to 6.5 meters.  Here the bile juice from the liver is found in the food which alkalizes the food in acidic medium and emulsifies the fat present in the food.  Pancreatic enzymes such as amylase, lipase, and trypsin are added to food.

 After digestion, food breaks down into its original particles, which the intestine walls absorb and send into our blood.  With the help of blood, this food is transported to every cell of the body.

 The oxidation of this food in the cells results in the release of energy which is used in the editing of various functions.

 Food left over from the small intestine now enters the large intestine, here the amount of water is absorbed from this undigested food, and the remaining undigested food is excreted through the anus.

 In this way, food is digested in humans.

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