7th Class Science Nutrition in Animals

Nutrition in Animals

Synopsis

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

• Nutrition in animals involves five steps-ingestion, digestion, absorption, assimilation and egestion.

• The human digestive system consists of the alimentary canal and digestive glands.

• We have 32 permanent teeth, which are classified into incisors, canines, premolars and molars according to their shapes and specific functions.

• The digestion process begins in the mouth. The saliva break down the starch into sugars.

• The stomach wall secretes gastric juice, which contain hydrochloric acid and pepsin. The acid kills many bacteria that enter along with the food.

• Liver secretes bile juice. The bile helps in the digestion and absorption of fats.

• The pancreatic juice secreted by pancreas acts on carbohydrates, fats and proteins.

• The intestinal juice completes the digestion of all components of the food.

• Large intestine absorbs water from the undigested food material.

• Food is absorbed into the blood stream through the villi in the wall of the small intestine.

• From the blood, the food molecules enter the body's cells, where they are assimilated and used for various life activities. Excess glucose is stored in the liver as glycogen.

• The portion of the tooth above the gum is called the crown. The portion inside the gum is called the root.

• The upper layer of the tooth which is hard is called enamel. The next inside layer is called dentine. The soft material inside the dentine is called pulp and it has blood vessels and nerves.

• The food stuck to teeth decays and damages our teeth. As a result, teeth get covered with a thin, sticky layer of germs called plaque. Plaque reacts with sugar and produces acids which spoil enamel of the teeth.

• The grazing animals like cows, buffaloes are known as ruminants. They quickly ingest and swallow their 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 vacuoles.