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Important questions based on NCERT syllabus for Chapter 2 - Nutrition in Animals:
Question-1: Write about the functions of Bile juices?
Solution: Bile juices will emulsify fats and break it down into small particles. This is a detergent-like action of bile which helps the body absorb the breakdown products of fat in the gut. In connection to this bile salts bind with lipids to form micelles. This is then absorbed through the intestinal mucosa.
Question-2: Write a brief note on villus.
Solution: A microscopic outgrowth on the surface of some tissues and organs, which serves to increase the surface area of the organ is called villi. Numerous villi line the interior of the small intestine. Their shape may vary from Unger-like (in the *duodenum) to spadelike (in the *ileum). Intestinal villi are specialized for the absorption of soluble food material: each contains blood vessels and a lymph vessel.
Question-3: Explain in detail how does food get digested in mouth?
Solution: Chewing food may accomplish the chemical, as well as the physical breakdown of food. This chemical degradation is achieved through the action of salivary glands. There are three sets of salivary glands in humans: parotid (just below the ear), submaxillary (in the region below the upper jaw), and sublingual (below the tongue). Each of them produce saliva, which passes down a short duct into the oral cavity. Saliva is a fluid rich in ions and contains some enzymes. Its major function is probably the wetting and lubrication of food particles. However, saliva also contains amylase (whose older name was ptyalin). Although ptyalin begins the breakup of starch that is ingested, food chewed in the mouth reaches the stomach rather quickly, and the acids in the stomach quickly inhibits the degradation of starch started in the mouth. Saliva also exerts an antibacterial action in the mouth and holds many harmful bacteria in check.