Digestive System Essay Type Questions And Answers
1. a) Would you describe food as fuel for animals?
Answer: Yes.
b) If you answered ‘yes’ or ‘no’ to the above, explain your answer.
Answer: It provides the body energy to operate.
c) What can be found in food?
Answer: Nutrients.
d) What are nutrients?
Answer: Nutrients are the substances that keep the body healthy.
e) Does food give the cells of our body the energy and nutrients they need to operate?
Answer: Yes.
2. What must happen before food can give the body energy?
Answer: It must be digested into smaller pieces the body can absorb and use.
3. What is digestion?
Answer: Digestion is the process whereby complex food substances are broken down by enzymes into simple soluble and absorbable forms in the body.
4. In humans, the process of nutrition begins with
Answer: ingestion (the taking in of food).
5. What must happen after ingestion?
Answer: The food has to be broken down into a simple, soluble and absorbable form in the body.
6. Digestion occurs in a long tube that starts from the mouth and ends at the anus. This tube is called
Answer: the alimentary canal.
7. Describe the path of digestion in the alimentary canal.
Answer: Mouth -> Oesophagus -> Stomach -> Duodenum -> Small intestines or Ileum -> Large intestines or Colon -> Rectum -> Anus.
8. Mention two organs that are part of the digestive system but are not part of the alimentary canal.
Answer:
· Liver.
· Pancreas.
9. The alimentary canal, together with a system of organs that carry out digestion, constitute
Answer: the digestive system.
10. State the function of the mouth.
Answer: Food is chewed in the mouth. Starch digestion begins in the mouth.
11. State the function of the oesophagus.
Answer: Muscles in the oesophagus contract and relax to push food through to the stomach.
12. State the function of the stomach.
Answer: The walls of the stomach secrete a digestive juice known as gastric juice. Protein digestion begins in the stomach.
13. State the function of the pancreas.
Answer: The pancreas produces a watery alkaline liquid known as pancreatic juice. Pancreatic juice contains digestive enzymes which digest starch, protein and fats and oil.
14. State the function of the liver.
Answer: The liver produces bile, which breaks down fats into tiny droplets in the duodenum.
15. State the function of the duodenum.
Answer: Digestion of starch, protein and fats and oil occur in the duodenum.
16. State the function of the ileum (small intestines).
Answer: Glands in the ileum secrete intestinal juice. This juice contains important enzymes which complete the process of digestion.
17. State the function of the colon (large intestines).
Answer: Excess water is absorbed from undigested food in the colon so that the undigested food becomes more solid.
18. State the function of the rectum.
Answer: Undigested food is stored as faeces in the rectum for some period of time.
20. State the function of the anus.
Answer: Undigested food comes out of the body through the anus.
21. Name the two distinct processes involved in digestion.
Answer:
· Physical (mechanical) process.
· Chemical process.
22. What is the physical process of digestion?
Answer: The physical process of digestion comprises chewing or mastication of food into smaller pieces in the mouth and the churning of the masticated food in the stomach.
23. What is the chemical process of digestion?
Answer: The chemical process involves reactions between the food and the digestive enzymes released along the alimentary canal.
24. What happens during digestion in the mouth?
Answer: Food is chewed (masticated) and mixed with saliva to make swallowing easy.
25. What is saliva?
Answer: Saliva is a watery alkaline substance produced by three pairs of salivary glands in the mouth.
26. Name the enzyme found in saliva and state its function.
Answer: Saliva contains an enzyme known as salivary amylase (ptyalin). The enzyme breaks down starch into maltose or sugar.
27. Is it true that starch digestion begins in the mouth?
Answer: Yes.
28. What happens to chewed and swallowed food?
Answer: The swallowed food passes through the oesophagus into the stomach by a process known as peristalsis.
29. What is peristalsis?
Answer: Peristalsis is the contraction and relaxation of the muscles in the alimentary canal to allow the passage of food.
30. What is the stomach?
Answer: The stomach is a muscular sac in which a meal is temporarily stored and passed on in convenient amount into the small intestine for digestion.
31. Does starch digestion stop in the stomach?
Answer: Yes.
32. Does protein digestion begin in the stomach?
Answer: Yes.
33. State the function of the walls of the stomach.
Answer: The walls of the stomach secrete a digestive juice known as gastric juice.
34. Name two things found in the gastric juice.
Answer:
· Hydrochloric acid.
· Enzymes.
35. Write three functions of the hydrochloric acid found in the gastric juice.
Answer:
· It provides an acidic medium in the stomach to stop the activity of ptyalin.
· It kills harmful bacteria that may be present in the food.
· It activates the enzymes found in the gastric juice.
36. Name the enzyme found in the gastric juice.
Answer: Pepsin.
37. Name the second enzyme found in the gastric juice of infants.
Answer: Rennin.
38. State the function of pepsin.
Answer: Pepsin converts protein into peptides.
39. State the function of rennin.
Answer: Rennin converts liquid protein (caseinogen) in the milk into solid protein (casein).
40. The first part of the small intestines is also called
Answer: the duodenum.
41. What happens to partly digested food in the stomach?
Answer: Partly digested food is passed on to the duodenum by the muscular contractions of the walls of the stomach.
42. Which digestive organ is close to the duodenum?
Answer: The pancreas.
43. Is the pancreas an enzyme secreting organ?
Answer: Yes.
44. What is pancreatic juice?
Answer: It is a watery alkaline liquid secreted by the pancreas.
45. a) Name the three important enzymes found in pancreatic juice.
Answer:
· Pancreatic amylase.
· Pancreatic lipase.
· Trypsin.
b) Which of the enzymes found in pancreatic juice is a protease?
Answer: Trypsin.
46. What does pancreatic amylase do?
Answer: It continues starch digestion by converting the remaining undigested starch into maltose.
47. a) What other organ is close to the proximal arm of the duodenum?
Answer: The liver.
b) What does the liver do?
Answer: It produces a greenish alkaline liquid known as bile.
c) Where does the liver store bile?
Answer: Gall bladder.
d) Where is the gall bladder located?
Answer: It is located below the liver.
48. What does bile do?
Answer: It breaks down fats into droplets for easy digestion.
49. Is it true that peristaltic movement passes on the food from the duodenum to the ileum?
Answer: Yes.
50. State the function of pancreatic lipase.
Answer: It acts on emulsified fat and converts them into fatty acids and glycerol.
51. Is it true that fatty acids and glycerol are the end products of fats and oil digestion?
Answer: Yes.
52. What does trypsin do?
Answer: It breaks down undigested proteins into peptides.
53. What is the ileum?
Answer: The ileum is the final and longest section of the small intestine.
54. Where is digestion completed?
Answer: Digestion is the completed in the ileum.
55. Is it true that partly digested food is absorbed in the ileum for some time during which many changes occur?
Answer: Yes.
56. a) Name the alkaline liquid produced by the enzyme producing cells in the ileum.
Answer: Intestinal juice.
b) Another name for intestinal juice is
Answer: succus entericus.
57. Name two important enzymes found in intestinal juice.
Answer:
· Maltase.
· Erepsin.
58. a) Is erepsin a protease?
Answer: Yes.
b) What does erepsin do?
Answer: It breaks down peptides to amino acids.
59. What does maltase do?
Answer: It breaks down maltose to glucose.
60. List the end products of digestion of the following food substances.
a) Starch (Carbohydrate)
Answer: Glucose.
b) Fats and oil
Answer: Fatty acids and glycerol.
c) Protein
Answer: Amino acids.
61. What do digestive enzymes do?
Answer: Digestive enzymes act on different food substances to break them down into smaller molecules or smaller pieces for easy absorption into the blood.
62. List the three main digestive enzymes and the food substance they act on.
Answer:
|
Digestive enzyme |
Food substance |
|
Amylase |
Starch or carbohydrate |
|
Protease |
Protein |
|
Lipase |
Fats and oil |
63. a) List three examples of proteases.
Answer:
· Pepsin.
· Rennin.
· Trypsin.
b) List two examples of amylase.
Answer:
· Salivary amylase.
· Pancreatic amylase.
c) Mention one example of a lipase.
Answer: Pancreatic lipase.
64. What is absorption of the end products of digestion?
Answer: Absorption is the passage of digested food into the blood stream by the process of diffusion through the villi.
65. What is the villi?
Answer: The villi are finger-like projections in the small intestines.
66. State what happens to absorbed glucose and amino acids.
Answer: They are transported by the bloodstream to the liver for storage.
67. What happens to excess glucose and excess amino acids?
Answer:
· Excess glucose molecules beyond the body’s requirement are converted into glycogen.
· Excess amino acids are converted into a nitrogenous compound known as urea.
68. a) Is fats and oil stored in the liver?
Answer: No.
b) Where does the body store fats and oil?
Answer: Fats and oil are stored in fat tissues.
c) Fat tissues are also known as
Answer: Adipose tissues.
d) Mention four areas of the human body where adipose tissues can be found.
Answer:
· Under the skin.
· Around the heart.
· Around digestive organs.
· Around reproductive organs.
69. Mention two food substances that are not broken down into smaller pieces in the body.
Answer:
· Minerals.
· Vitamins.
70. State what happens to minerals and vitamins in the body.
Answer: They simply diffuse into the blood together with the end products of digestion.
71. Does the blood transport the absorbed food substances to all tissues and organs of the body?
Answer: Yes.
72. State the use of glucose.
Answer: It combines with oxygen in the cells to produce energy which is used for body activities.
73. State the use of fatty acids and glycerol.
Answer: It serves as a source of energy in the body.
74. State three uses of amino acids.
Answer:
· It is used to make materials that are used to repair worn out tissues.
· It is used in the formation of enzymes.
· It is used in the formation of hormones.
75. What is egestion?
Answer: Egestion is the process whereby undigested food comes out of the body through the anus.
76. State where undigested food is stored for a period of time after excess water has been absorbed from it in the colon.
Answer: Rectum.
77. How is undigested food removed from the body?
Answer: It comes out of the body through the anus in a semi-solid state known as faeces.
78. What is indigestion?
Answer: Indigestion is the condition in which food is not properly broken down into simpler units in the digestive system.
79. State five causes of indigestion.
Answer:
· Lack of roughage and fluid in diet.
· Eating meat or food that has not cooked well.
· Overeating.
· Sleeping immediately after a heavy meal.
· Eating too fast.
80. State four effects of indigestion.
Answer:
· Nausea.
· Stomach ache.
· Severe abdominal pains.
· Burning sensation in the stomach.
81. What is constipation?
Answer: Constipation is the difficulty in freeing the bowels regularly.
OR
Constipation is the irregular and difficult passage of faeces.
82. Why does constipation occur?
Answer: Constipation occurs when faeces remain in the rectum for too long and a lot of water is removed from the faeces. This makes the faeces hard, dry and difficult to be expelled from the bowels.
84. State four causes of constipation.
Answer:
· Lack of physical exercise.
· Taking little or no water after meals.
· Eating foods that contain less fibre or roughage.
· Eating foods that contain less vegetable.
85. State five effects of constipation.
Answer:
· Headache.
· Abdominal pains.
· Loss of appetite for food.
· General body pains.
· Tiredness.
· Cancer of the anus.
86. State five ways of preventing constipation.
Answer:
· Exercise the body regularly.
· Avoid overeating.
· Drink enough water after every meal.
· Eat plenty of fruits and vegetables.
· Increase intake of roughage or fibre.
· Free your bowels regularly.
87. State the connection between the digestive, respiratory and the circulatory system.
Answer:
Digestive system breaks down food into glucose. A part of the glucose is used for respiration. Respiration (respiratory system) produces energy, carbon dioxide and water. The energy is used by the entire body. The heart (circulatory system) uses it to pump blood around the body.
88. What would happen if the circulatory system fails to transport blood to all parts of the body and the digestive system fails to perform its function?
Answer: Respiration requires oxygen and glucose in humans. Oxygen is carried by the blood to the lungs; glucose is produced by the digestive system. If these fail, there would be no respiration which would lead to a crisis because every living organism needs energy to operate.
89. Draw a flow chart to show the end products of digestion for the following food substances.
a) Starch
Answer: Starch -> Maltose -> Glucose
b) Protein
Answer: Protein -> Peptides -> Amino acids
c) Fats and oil
Answer: Fats and oil -> Tiny droplets -> Fatty acids and glycerol