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STD . 7th, , Sub:Science, 12. Muscular System and Digestive System, SUMMATIVE EVALUATION, QUESTIONS AND ANSWERS, , Q. 1. Fill in the blanks with the right word from the brackets:, (1) The process of digestion starts from the mouth (stomach / mouth), (2) Eyelids have voluntar muscles. (voluntar/ involuntary), (3) Production of blood cells is not a function of the muscular system. (Production of blood, cells/ Performing movements), (4) Muscles of the heart are cardiac muscles (ordinary muscles / cardiac muscles), (5) Pushing forward the food that has been chewed is the function of the oesophagus ., (stomach/oesophagus), (6) Muscles are bundles of fibres that can contract and relax as required. (cells/fibres), (7) In blood vessels and uterus there are smooth muscles (skeletal / smooth), Q. 2. Who is telling a lie?, Organ, (1) Tongue, (2) Liver, (3) Large intestine, (4) Appendix, (5) Lung, Ans., , Statement, My taste-buds can tell only a sweet taste., I am the largest gland in the body, I am 7.5 meter long, Digestion is impossible without me, I play an important role in excretion, , (1) Tongue is lying. It can sense all the different tastes., (2) Liver is telling the truth., (3) Large intestine is lying. Its length is 1.5 meter long., (4) Appendix is lying. It does not perform any function in human body., (5) Lung is telling a partial lie. It can perform function of excretion. But not as import role, as performed by kidney.., Q. 3. Find a match for me :, Group 'A', Group 'B', (1) Cardiac muscles, we never feel tired, (2) Are brought about by muscles Chewing movements of jaws, 3) Pepsin, Enzyme of gastric juice
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(4) Cramps, (5) Skeletal muscles, , uncontrolled and painful contraction of muscles, always function in pairs, , Group 'A', (1) Weight of muscles of a healthy man, (2) Total number of muscles in the human body, (3) Facial muscles, (4) Heart beats per minute, Group 'A', (1) Biceps, (2) Flexors, (3) Quadriceps, (4) Deltoid, (5) Triceps, , Group 'B', 40%, 600, 30%, 20%, , Group 'B', front side of upper arm, shank, thigh, shoulder, back side of upper arm, , Q. 4. Give Reasons:, (1) Food becomes acidic in the stomach., Ans. The wall of the stomach has gastric glands that produce mild hydrochloric acid, ue to, this the food becomes acidic in the stomach., (2) Cardiac muscles are said to be involuntary muscles., Ans. The muscles of heart do not function according to our will. They continuously work, roughout the life time by involuntary, smooth muscles., (3) Intoxicating substances should not be consumed., Ans. Consuming intoxicating addictive substances can cause harm to our health. tobacsco,, smoking cigarettes, consuming alcohol are bad addictive habits. Some of these also se, cancer of various organs. The functioning of the systems of the body is disturbed due To, such habits. Therefore, intoxicating substances should not be consumed., (4) Your muscles should be strong and efficient., Ans. The muscles of the body become strong and healthy due to proper proteinaceous det, and exercise. With such muscles, we can perform many activities. If the muscles are not, healthy, there can be various painful problems therefore the muscles should be strong, and effcient., Q. 5. Answer the following questions in one sentence:, (1) How many types of muscles are there? Which are those types?, Ans. The muscles are of three main types, viz. (1) Skeletal or voluntary Cardiac muscles (3), Smooth or involuntary muscles.
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(2) During digestion, does all the food that we have eaten get converted into useful,, nutritive substances?, Ans. All the food that we eat does not get digested into nutritive substances. mains, undigested and eventually thrown out of the body through anus., (3) Which parts of our body are made up only of muscles?, Ans. Heart, blood vessels, diaphragm located between the thoracic and abdominal cavity, and the uterus in female body are entirely made up of muscles., (4) What would happen if: The cardiac muscles do not move., Ans. If cardiac muscles do not move, the heart will stop its beating. There will be no od, supply of vital organs like brain and the death will follow., Q.6. Answer the following questions in short:, (1) What causes the problem of acidity? What is its effect on the body?, Ans. Acid is produced by stomach. It is mild 0.5 % HCL. If excess of acid is produced it uses, headache, heart burns, vomiting or skin rashes,, (2) Name the different types of teeth. What is the function of each type?, Ans. There are main four types of teeth. These are incisors, canines, premolars and, molars. Incisors help in biting, breaking something into a piece or for peeling. Canines are, not well developed in herbivorous animals and man. They are basically for killing a prey., Premolars and molars help in chewing and grinding the food., (3) Which enzymes help in the digestion of proteins?, Ans. The protein digesting enzymes are as follows: (1) Pepsin from stomach and (2), Trypsin from pancreas. There are some additional enzyme in the small intestinal juices too, (4) How do we affect our health adversely?, Ans. Improper diet, lack of exercise and bad habits affect our physical health. If we resort, to addictive habits like smoking, chewing of tobacco, drinking alcohol, it affects our health, adversely., (5) What would happen if : Food enters the stomach and the stomach muscles do not, move., Ans. If the muscles of the stomach fail to function, the mechanical digestion of food will, stop. The food will not be digested and sent further. It will remain in the stomach and get, putrefied (decayed). This will cause harm to the health., (6) What soluble nutrients are formed after the digestion of food?, Ans. The proteins are broken down into amino acids. The complex carbohydrates are, converted into simple sugars. The fats are converted into fatty acids and glycerol. Thus
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amino aids, sugar and fatty acids-glycerol are the nutrients formed after the digestion of, food., Q. 7. Answer the following questions with neat and well-labelled diagrams:s, (1) Sketch and label a diagram of the digestive system and describe it in your own words., Ans. The digestion of food starts from mouth cavity., (1) Mouth: The food that is ingested is broken down into small bits by teeth. The tongue, helps to understand the taste. The food is mixed with saliva by tongue. After the morsel is, gulped it enters the pharynx., (2) Pharynx: In the pharynx the oesophagus and trachea open. When food is gulped the, small flap called epiglottis covers the opening of traches. This makes the food to enter into, oesophagus., (3) Oesophagus: This is the first part of the alimentary canal. It starts from pharynx and, ends in stomach., (4) Stomach: The stomach is a large J shaped bag. There are gastric glands in the wall, stomach. They secrete gastric juice. It has mild hydrochloric acid, pepsin and mucus. The, and is churned into semi solid slurry and mixed with gastric juice in the stomach., The food becomes acidic in the stomach. The preliminary digestion of proteins is done by, enzyme pepsin present in the gastric juice. The mucus protects the inner lining of the, stomach. The slurry of semi digested food is passed into small intestine from the stomach., (5) Small intestine: Small intestine is a very long, narrow tube like part of alimentary, canal. It is about 6 metre long. Here two main functions take place, viz. completion of, digestion and absorption of nutrients. The intestinal juice from wall of small intestine, the, bile juice, secreted by the liver and the pancreatic juice secreted by the pancreas are, mixed with the food here. The digestive enzymes from these secretions act on the food, and complete the process of digestion here. The soluble nutrients which are not ready are, absorbed in the blood vessels., (6) Large intestine: Large intestine is about 1.5 metres and is wider in diameter. It has two, parts, colon and rectum. There is small functionless appendix near the beginning of large, intestine. The water is reabsorbed here in the large intestine and the faces is formed. The, undigested and unwanted matter from the food is thrown out through the anus.
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(7) Associated digestive glands: The digestive glands are as follow:, (i) Salivary glands: Three pairs of salivary glands open in the mouth. They are located near, ear, under the tongue and in the pharynx. These glands secret saliva which contains, salivary amylase or ptyalin. The food is mixed with this enzyme in the mouth. Starch is, converted into maltose by this enzyme., (ii) Liver: Liver is the largest gland in the human body. It stores the glucose. There is gall, bladder near the liver. The bile juice secreted by the liver is stored in the gall bladder. The, bile juice helps in the emulsification of fats. Bile juice contains bile slats and bile pigments.
