Q21. The involuntary muscle movements that deliver food to the stomach are known as:
a) Peristalsis
b) Mastication
c) Segmentation
d) Deglutition
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Correct Answer: a) Peristalsis
Explanation: Peristalsis refers to the involuntary wave-like muscle contractions that move food along the digestive tract, from the esophagus to the stomach. This movement is essential for the progression of food through the digestive system.
Q22. Which organ is NOT a part of the alimentary canal?
a) Esophagus
b) Small intestine
c) Liver
d) Stomach
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Correct Answer: c) Liver
Explanation: The liver is not a part of the alimentary canal but an accessory organ in the digestive system. The alimentary canal, or the digestive tract, includes organs through which food actually passes, like the esophagus, stomach, and small intestine.
Q23. What enzyme in saliva breaks down starches into simpler sugars?
a) Protease
b) Amylase
c) Lipase
d) Lactase
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Correct Answer: b) Amylase
Explanation: Amylase in saliva is responsible for breaking down starches (complex carbohydrates) into simpler sugars, like maltose. This is the initial step in the chemical digestion of food in the mouth.
Q24. The majority of nutrient absorption occurs in which part of the digestive system?
a) Stomach
b) Small intestine
c) Large intestine
d) Colon
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Correct Answer: b) Small intestine
Explanation: The small intestine is the primary site for nutrient absorption. Its highly folded surface area, with villi and microvilli, provides an optimal environment for absorbing nutrients into the bloodstream.
Q25. The appendix is attached to which part of the large intestine?
a) Ascending colon
b) Descending colon
c) Cecum
d) Sigmoid colon
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Correct Answer: c) Cecum
Explanation: The appendix is a small, tube-like structure attached to the cecum, which is the beginning of the large intestine. Its function is not fully understood, but it is believed to play a role in the immune system.
Q26. Hydrochloric acid in the stomach performs what function?
a) Breaking down carbohydrates
b) Neutralizing stomach acid
c) Activating digestive enzymes
d) Absorbing vitamins
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Correct Answer: c) Activating digestive enzymes
Explanation: Hydrochloric acid in the stomach has several functions, including activating pepsinogen into pepsin (a digestive enzyme for proteins), creating an acidic environment for digestion, and acting as a barrier to pathogens.
Q27. Gastric juice in the stomach consists mainly of:
a) Water, hydrochloric acid, and pepsin
b) Bile and pancreatic enzymes
c) Mucus and bicarbonate
d) Amylase and lipase
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Correct Answer: a) Water, hydrochloric acid, and pepsin
Explanation: Gastric juice, produced by the stomach, primarily consists of water, hydrochloric acid, and pepsin. It is crucial for digesting food, especially proteins, and maintaining an acidic environment in the stomach.
Q28. The duodenum, jejunum, and ileum are parts of the:
a) Large intestine
b) Stomach
c) Small intestine
d) Pancreas
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Correct Answer: c) Small intestine
Explanation: The small intestine is divided into three sections: the duodenum, jejunum, and ileum. It plays a crucial role in digesting food and absorbing nutrients. The duodenum receives digestive enzymes from the pancreas and bile from the liver.
Q29. The primary function of the colon is to:
a) Digest proteins
b) Absorb water and electrolytes
c) Produce bile
d) Secrete digestive enzymes
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Correct Answer: b) Absorb water and electrolytes
Explanation: The primary function of the colon, or large intestine, is to absorb water and electrolytes from the remaining indigestible food matter. This process helps form solid waste (feces) from the remaining food residue.
Q30. Chyme refers to:
a) Chewed food in the mouth
b) Food mixed with saliva
c) The semi-liquid mass in the stomach after digestion
d) Absorbed nutrients in the bloodstream
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Correct Answer: c) The semi-liquid mass in the stomach after digestion
Explanation: Chyme is the semi-liquid mass of partially digested food that forms in the stomach and is passed into the small intestine. It results from the mechanical and chemical digestion of food in the stomach.