NUTRITION IN ANIMALS Class 7 ncert notes II Summary of Chapter II Keywords II Question and Answers II NCERT II CBSE II Class 7 Science II

SUMMARY

The process of taking in food by the living organism and its utilization in the body is called as Animal Nutrition.

Animal nutrition includes nutrient requirement, mode of intake of food and its utilization in the body.

Components of Food:

It includes complex substances like Carbohydrates, Fats, Proteins and Vitamins. Minerals, Roughage and are called as NUTRIENTS.

The breakdown of complex components of food into simpler substances is called digestion.

Mode of intake of food 

Bees and humming-birds suck the nectar of plants, 

Snakes like the python swallow the animals they prey upon. 

Aquatic animals filter tiny food particles floating nearby and feed upon them.

Scraping, chewing, siphoning, capturing and swallowing, sponging, sucking are the different modes of food intake.

Steps in Animal Nutrition:

Nutrition in animals takes place in Five steps:

Ingestion Digestion Absorption Assimilation and Egestion.

The digestive tract and the associated glands together constitute the digestive system

Human digestive system consists of a long alimentary canal or digestive tract. The canal can be divided into various compartments:

PART OF DIGESTIVE SYSTEM	STEP IN NUTRITION	FUNCTION
MOUTH and BUCCAL CAVITY	Ingestion	The saliva breaks down the starch into sugars.
OESOPHAGUS		Pushing down food
THE STOMACH	Digestion	Secretes mucous, hydrochloric acid and digestive juices. Breakdown of proteins
SMALL INTESTINE	Absorption and Assimilation	Digestion of all components of the food. Carbohydratesàglucose, Fats àfatty acids +glycerol Proteins àamino acids
Liver		It secretes bile juice that is stored in the gall bladder. Digestion of fats.
Pancreas		Digestion of carbohydrates, fats and proteins
LARGE INTESTINE	Egestion	Absorb water and some salts from the undigested food material.

DIGESTION IN GRASS-EATING ANIMALS

Cows, buffaloes, cattle, deer and other grass-eating animals chewing continuously even when they are not eating.

The digestive system consists of:

Esophagus

Stomach (Rumen)

Caecum

Small Intestine

Large Intestine

They quickly swallow the grass and store it in a part of the stomach called rumen.

The food get partially digested and is called cud.

Later the cud returns to the mouth in small lumps and the animal chews it. This process is called rumination.

The grass is rich in cellulose, a type of carbohydrate, the bacteria present in rumen helps in digestion of cellulose.

A large sac-like structure called Caecum between the oesophagus and the small intestine.

The cellulose of the food is digested here by the action of certain bacteria.

KEYWORDS:

• 1.       Absorption: Absorption is the process by which digested food materials are taken up into the bloodstream from the walls of the small intestine.
• 2.       Amino acid: Amino acids are building blocks of proteins.
• 3.       Amoeba: Amoeba is a microscopic single-celled organism found in pond water.
• 4.       Assimilation: The process of building complex substances by the absorbed food in the body
• 5.       Bile: Bile is a digestive juice secreted by Liver that plays an important role in the digestion of fats.
• 6.       Buccal cavity: A cavity lies at upper end of alimentary canal. It has three parts-Palate, Tongue, Teeth.
• 7.       Canine: Type of teeth that helps in Tearing and Piercing. They are 4 in number
• 8.       Cellulose: A type of carbohydrate that is present in grass.
• 9.       Digestion: The process of breakdown of complex substances into simpler substances
• 10.   Egestion: Removal of faecal matter through the anus is called Egestion.
• 11.   Fatty acid: A component of Fats. The are the building blocks of fat in our body
• 12.   Food vacuole: A membrane structure in amoeba that helps in digestion.
• 13.   Gall bladder: A sac like structure that stores the bile juice.
• 14.   Glycerol: A simple compound that is the component of fats.
• 15.   Incisor: A set of teeth that helps in Cutting and Binding. They are 8 in number
• 16.   Ingestion: The process of taking food into the body is called Ingestion.
• 17.   Liver: The liver is a gland situated in the upper part of the abdomen on the right side. It is the largest gland in the body and secretes bile juice.
• 18.   Milk teeth: The first set of teeth which grows during infancy and fall off at the age of six to eight years
• 19.   Molar: A set of teeth that helps in Chewing and Grinding. They are 12 in number
• 20.   Permanent teeth: The second set of teeth in a child which replaces his milkteeth
• 21.   Oesophagus: It is a tube that connects the mouth and the stomach, also known as the Food Pipe, where swallowed food travels into the stomach.
• 22.   Pancreas: The pancreas is a large gland located just below the stomach which produces pancreatic juice acts on carbohydrates, fats and proteins and changes them into simpler forms.
• 23.   Premolar: A set of teeth that helps in Chewing and Grinding. They are 8 in number.
• 24.   Pseudopodia: The finger-like projections in amoeba are called pseudopodia. They are also called as False Feet.
• 25.   Rumen: A part of the stomach that stores the quickly eaten grass by ruminants.
• 26.   Ruminant: The grass eating animals like cow, cattle, deer that digests cellulose by bacteria present in their rumen are called as Ruminants.
• 27.   Rumination: The process of food getting partially digested (cud) in rumen of animals like cow, which returns to its mouth and is then chewed for long.
• 28.   Salivary glands: The glands located in the mouth that secrete a watery material called saliva.
• 29.   Villi: The inner walls of the small intestine have thousands of finger-like outgrowths called villi. It absorbs the digested food materials.
• 30.   Saliva: A watery material secreted by Salivary glands. Its function is digestion of carbohydrates in mouth.