Nutrition in Animals 1

SPLENDID SCIENCE—CLASS 7. Section 2.1 Modes of obtaining food.

Animals. [image]. Animals are heterotrophs. They get nutrition from plants and other animals. Heterotrophs are therefore called consumers. Animal nutrition includes the mode of intake of food based on nutrient requirements, and its utilisation in the body. All animals do not take in their food in the same way..

Chewing A method in which food is first torn or crushed into smaller pieces and then taken into the body. In the mouth, the pieces of food are chewed. Animals with well-defined teeth or hard gums such as humans, cows, goats, and monkeys use this mode to take in food..

Siphoning A method in which food is sucked off using a thin tube-like mouth part called the siphon. Animals such as butterflies and bees use this mode for food intake..

Starfish shows a special method of taking in its food. It includes small-shelled animals such as mussels and clams. It feeds by first extending its stomach out of its mouth and over the digestible parts of its prey. The prey tissue is partially broken down externally and then the stomach of the starfish is drawn back inside its body along with the partially broken down prey..

A. Read each statement and give one word for each statement that describes each process. Transportation of absorbed food to different parts of the body and their utilisation. ……………………… Breaking of complex food substances into simpler and soluble substances. ……………………… Removal of undigested and unabsorbed solid residues of food from the body. ……………………… Taking food into the body. ……………………… Transport of digested and soluble food from the intestine to blood vessels. ……………………… B. Match the column. Animals Mode of Feeding Housefly a. Biting and chewing Cockroach b. Sucking Snail c. Sponging Mosquitos d. Scraping.

Nutrition in humans One of the main functions of nutrition is to break down or disassemble the food we eat into smaller components such that they can be used as energy for the body..

Digestive Process Digestion begins with ingestion, that is, when we put food into our mouth. The system takes the ingested food and begins moving it through the digestive tract. As food undergoes digestion, the complex food molecules are broken down both mechanically and chemically. The digestive system absorbs the digested food and sends it to millions of cells that form a part of our body. In the cells, the simpler molecules are assimilated, or utilised by the body. Finally, the materials that cannot be digested are egested or eliminated from the body..

Around the age of six, the milk teeth start falling out, giving way to permanent teeth. By the age of about 21 years, the average person has 32 permanent teeth—16 in the upper jaw and 16 in the lower jaw..

Parts of a tooth Crown—The top part of a tooth, and the only part you can normally see. The shape of the crown determines the tooth’s function. Root—The part of a tooth that is embedded in the bone. The root makes up about two-thirds of the tooth and holds the tooth in place. Enamel—The outermost layer of a tooth. Enamel is the hardest, most mineralised tissue in the body—yet it can be damaged by decay if teeth are not looked after properly. Dentine—The layer of a tooth under the enamel. If decay is able to progress its way through the enamel, it next attacks the dentine. Pulp—The soft tissue found in the centre of a tooth, where the nerve tissue and blood vessels are. If tooth decay reaches the pulp, you usually feel pain..

Over time, the acids made by the bacteria eat away the tooth enamel, causing cavities. This is called tooth decay. If it is not treated in time, in severe cases, this could result in tooth loss. Therefore, when we eat food items such as chocolates, sugary soft drinks, raisins or other sticky dried fruits, cakes, fruit juices and bread, we must remember to brush and floss our teeth. Flossing involves using a special strong thread called dental floss to clear food particles by moving them between two adjacent teeth..

Digestion in humans. The process by which food is broken down into simpler forms that can be absorbed by the body is called digestion. Digestion of food starts in the mouth itself..

The oesophagus is a muscular tube that connects the mouth to the stomach. Food moves down the oesophagus to the stomach by a series of contractions along the walls of the digestive tract..

From the oesophagus, food passes through a circular muscle called a sphincter and into the stomach. The condition commonly known as heartburn is the result of some stomach acid leaking through the sphincter back into the oesophagus. The stomach lining secretes mucus, which forms a protective layer between the stomach lining andthe acidic environment of the stomach. Food stays in the stomach for about 2–4 hours; during this time the mechanical digestion and chemical digestion change the consistency of the food to a semi-liquid state. The stomach muscles now move to push small amounts of this material into the small intestine..

Liver The liver is a large, complex organ that has many functions. It is a reddish-brown organ situated on the upper right side of the abdomen area. The liver secretes bile, a chemical substance that breaks down fats. When the liver makes bile, it is stored in the gall bladder. Gall bladder The gall bladder is a small organ located just under the liver. Bile passes from the gall bladder into the bend in the small intestine..

Sometimes the diaphragm—a sheet of muscles below the lungs—moves down with a jerk, which causes air to enter very fast. The air rushing in causes the flap at the top of our windpipe to shut briefly causing hiccups. Most hiccups last only a few minutes. Anything that relaxes the diaphragm usually stops the hiccups..

The amino acids help in growth and repair. The fatty acids and glycerol are stored and used as energy reserves..

Match the column. Oesophagus a. It has teeth that breaks the food into small pieces. Large intestine b. It is a long tube. Food goes down here to the stomach. Anus c. It is a muscular bag. The food stays here for about three hours Stomach d. It is a very long thin tube. There are lots of blood vessels around the tube. Small intestine e. What our body doesn’t need goes out through it when we go to the toilet. Mouth f. It is a wide tube. It connects to the anus..

Nutrition in grass-eating animals. A grass-eating animal such as a cow, continuously chewing as its jaws are constantly moving sideways as if grinding something. This is called ‘chewing the cud’. ‘Cud’ is a lump of semi-digested food that returns from the animal’s stomach to the mouth to be chewed for the second time. Bringing up the cud into the mouth is called regurgitation. The process of bringing the swallowed food back into the mouth to be chewed again is called rumination. Herbivores that can bring the swallowed food back into their mouths to chew it again are called ruminants. Animals such as cows, buffaloes, goats and sheep are examples of ruminants. Ruminants They feed on plants but cannot easily digest a carbohydrate called cellulose, present in plants such as grass. Rumination helps these animals mechanically digest the cellulose by repeated chewing. When ruminants graze, they quickly swallow as much plant material as they want without much chewing. This method of digesting food in plant-eating animals makes their digestive system different from that of other animals such as humans..

The upper jaw of cows does not have teeth, but has a hardened gum. Cows do not thoroughly chew their food when they first ingest it, in order to maximise the amount of food they are able to consume in a short amount of time. When a cow ‘chews its cud’, some of the larger food particles are regurgitated, chewed again and re-swallowed. This rumination mostly occurs when the cow is not actively eating. Mechanical digestion begins in the mouth with chewing in order to reduce the particle size of the plants ingested. This enables digestive juices to have easier access to the food. Digestive juices in saliva are mixed with food before it passes down the oesophagus, the tube that leads to the stomach chambers..

This regurgitated mixture of partially digested materials and microorganisms then travels back through the rest of the digestive tract for further digestion. The reticulum is connected to the spherical omasum by a short tunnel. The reticulum mixes and stirs the material, and also provides an additional area for fermentation. In the omasum, the particle size of the semi-digested food is reduced, and any excess water is removed before it enters the abomasum. The fourth compartment is the abomasum or ‘true stomach.’.

Just like in humans, the small intestine contains numerous microscopic structures that help in nutrient absorption. Muscular contractions of the intestine mix the digested food and move it along the tract. Any undigested matter that remains is passed on to the large intestine..

Nutrition in Amoeba Amoeba, like other heterotrophic animals, follows the 5-step process for acquiring nutrition..

Fill in the blanks. False feet of Amoeba is called …………………………………… The finger-like outgrowths of Amoeba help to …………………………………… food. Cud is the name given to the food of ruminants which is …………………………………… and partially digested. Ruminant stomachs have …………………………………… compartments. …………………………………… helps in digestion in amoeba..

Choose the correct answer. What is the finger-like projections in the wall of the small intestine? i. Taste buds ii. Absorbed water iii. Villi iv. Mucus (b) What are tearing teeth? i. Molars ii. Incisors iii. Premolars iv. Canines (c) The enzymes present in saliva convert i. fats into fatty acids and glycerol. ii. proteins into amino acids. iii. starch into simple sugars. iv. complex sugars into simple sugars. (d) Choose the organ which is part of alimentary canal. i. Large intestine ii. Pancreas iii. Liver iv. Gall bladder (e) Amoeba procures food through i. probosis ii. pseudopodia iii. cilia iv. tongue.