Class 7 Science Chapter 2 Notes Nutrition in Animals
→ Absorption : Digested food passes through the walls of small intestine and goes into the blood. This process is called absorption.
→ Amino acid : Proteins are broken into simpler forms, i.e. amino acid during digestion.
→ Amoeba : It is a microscopic single-called organism, found in pond water.
→ Assimilation : After digestion in small intestine absorbed substances are transported via the blood vessels to different organs of the body where they are used to build complex substances. This is called assimilation.
→ Assimilation : After digestion in small intestine absorbed substances are transported yia the blood vessels to different organs of the body where they are used to build complex substances. This is called assimilation.
→ Bile : It is the digestive juice secreted by liver. Bile plays an important role in the digestion of fats.
→ Buccal cavity : Mouth opening is called buccal cavity. It is the starting point of alimentary canal.
→ Canine : Pointed tooth between incisor and premolar is called Canine. This is used for piercing and tearing of food.
→ Cellulose : Cellulose is a complex carbohydrate substance. Cellulose is rich in grass.
→ Digestion : The breakdown of complex components of food in to simpler substances is called digestion.
→ Egestion : Process of removal of undigested food from body is called Egestion.
→ Fatty acid : During digestion, fat is broken down into fatty acids by the action of enzymes.
→ Food vacuole : Amoeba has small bubble like vacuoles in cytoplasm. Food is digested in these vacuoles. So, these are called food vacuoles.
→ Gall bladder : It is a small pouch like organ that stores bile juice secreted by liver.
→ Glycerol : The end product of digestion of fats is glycerol.
→ Incisors : The four front teetch in both the upper and lower jaws are called incisors. They are used for cutting and biting.
→ Ingestion : Method of taking food inside the body is called ingestion.
→ Liver : It is the reddish gland situated in the upper part of the abdomen on the right side. It is the largest gland in the body. It secretes bile juice.
→ Milk teeth : The first set of teeth grows during infancy and they fall off at the age between six to eight years. These are termed milk teeth.
→ Molar : The crushing teeth that occur at the back of the jaw are called molar.
→ Permanent teeth : The second set of teeth that replaces milk teeth are called permanent teeth.
→ Oesophagus : It is also called food pipe is a pipe in which food travels from mouth to stomach.
→ Pancreas : It is the large cream coloured gland located just below the stomach. The pancreas secretes pancreatic juice.
→ Premolar : These are the teeth situated between canine and molar teeth. These are used to chew and grind the food.
→ Pseudopodia : Finger like projections of Amoeba that helps it to move and capture the food are called pseudopodia or false feet.
→ Rumen : It is the first part of stomach of grass eating animals. Food is partially digested here and called cud.
→ Ruminant : Animals that perform the process of rumination are called ruminants.
→ Rumination : A process by which partially digested food by ruminants returns to their mouth and are again chewed properly is called rumination.
→ Salivary glands : Salivary glands are the glands present in our mouth which – secretes saliva.
→ Villi : The inner walls of the small intestine have thousands of finger – like projections. These are called Villi.
→ Saliva : Saliva is a digestive juice secretes from salivary glands. It contains salivary amylase which breaks down the complex sugars in simpler sugars.
→ Animals get their food from plants, either directly or indirectly.
→ Animal nutrition includes nutrient requirement, mode of intake of food and it’s utilisation in the body.
→ The human digestive system consists of the alimentary canal and secretory glands. It consists of
- buccal cavity,
- oesophagus,
- stomach,
- small intestine,
- large intestine ending in rectum and
- Anus.
→ The main digestive glands which secrete digestive juices are
- the salivary glands,
- the liver and
- the pancreas.
The stomach wall and the wall of the small intestine also secrete digestive juices.
→ Nutrition is a complex process involving :
- ingestion,
- digestion,
- absorption,
- assimilation and
- egestion.
The nutrition in human beings is holozoic nutrition.
→ There are different types of teeth, namely
- Incisors
- Canines
- Premolars
- Molars.
Tooth is the hardest part of our body.
→ Lactic Acid produced by the bacteria causes destruction of enamel of teeth.
→ At the end of the digestion, carbohydrates are converted into glucose, proteins are converted into amino acids and fats are converted into glycerol and fatty acids. These are absorbed in small intestine.
→ The absorbed substances are transported to different parts of the body. Water and some salts are absorbed from the undigested food in the large intestine.
→ The undigested and unabsorbed residues are expelled out of the body as faeces through the anus.
→ The grazing animals like cows, buffaloes and deer are known as ruminants. They quickly ingest, swallow their leafy food and store it in the rumen. Later, the food returns to the mouth and the animal chews it peacefully.
→ Amoeba ingests its food with the help of its false feet or pseudopodia. The food is digested in the food vacuole.
→ The basic process of digestion of food and release of energy is the same in all animals.