Nokea
Which of the following is true regarding the small intestine?
- A. It produces digestive enzymes
- B. It absorbs nutrients
- C. It produces bile
- D. It stores waste
Correct Answer: B
Rationale: The correct answer is B because the small intestine is primarily responsible for absorbing nutrients from digested food. It has specialized structures like villi to maximize nutrient absorption. Choice A is incorrect as the pancreas and other organs produce digestive enzymes. Choice C is incorrect as the liver produces bile. Choice D is incorrect as waste is stored in the large intestine, not the small intestine.
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Salivary secretion:
- A. Starts digestion of carbohydrates.
- B. is under control of secretin hormone.
- C. Starts digestion of proteins.
- D. is highly acidic.
Correct Answer: A
Rationale: The correct answer is A because salivary secretion contains enzymes like amylase that start the digestion of carbohydrates in the mouth. This enzyme breaks down complex carbohydrates into simpler sugars. Choices B, C, and D are incorrect because salivary secretion is not directly controlled by secretin hormone, does not start the digestion of proteins, and is not highly acidic. Salivary secretion primarily aids in the initial breakdown of carbohydrates, preparing them for further digestion in the stomach and intestines.
The enzymes present in pancreatic juice are
- A. Amylase, Trypsinogen, Peptidase, Rennin
- B. Trypsinogen, Lipase, Amylase, Procarbo xypeptidase
- C. Peptidase, Pepsin, Amylase, Rennin
- D. Maltase, Amylase, Trypsinogen, Pepsin
Correct Answer: B
Rationale: The correct answer is B because pancreatic juice contains enzymes such as Trypsinogen, Lipase, Amylase, and Procarboxypeptidase. Trypsinogen helps in protein digestion, Lipase breaks down fats, Amylase digests carbohydrates, and Procarboxypeptidase aids in protein digestion.
Choice A is incorrect because it includes Rennin, which is not typically found in pancreatic juice. Choice C is incorrect because Pepsin is a stomach enzyme, not found in pancreatic juice. Choice D is incorrect because Maltase is an enzyme found in the small intestine, not in pancreatic juice.
Saliva is needed for:
- A. Digestion of sucrose
- B. Digestion of phospholipids
- C. Ability to speak
- D. Breaking food down into small pieces
Correct Answer: A
Rationale: Saliva contains an enzyme called amylase, which helps break down sucrose (a type of sugar) into glucose and fructose for digestion. Therefore, the correct answer is A. Saliva does not play a significant role in the digestion of phospholipids (B), speaking ability (C), or breaking food down into small pieces (D).
The absorption of fructose by intestinal mucosa is
- A. co- transport mechanism
- B. simple diffusion
- C. facilitated transport
- D. active transport
Correct Answer: C
Rationale: The correct answer is C: facilitated transport. Fructose is absorbed through facilitated diffusion using specific carrier proteins in the intestinal mucosa. This process does not require energy input and allows fructose to move down its concentration gradient. Unlike active transport (requiring energy) and co-transport mechanisms (involving multiple substances), fructose absorption occurs through facilitated transport by specific carrier proteins. Simple diffusion is not the main mechanism for fructose absorption due to its hydrophilic nature. Thus, facilitated transport best describes how fructose is absorbed by the intestinal mucosa.
Which of the following mechanisms most accurately describes how pseudo-membranous colitis caused by Clostridium difficile is produced?
- A. elaboration of an enterotoxin following colonization of the colon
- B. ingestion of a preformed toxin
- C. invasion and destruction of mucosa by the organism
- D. host immune response to the organism
Correct Answer: A
Rationale: The correct answer is A because Clostridium difficile produces toxins, specifically enterotoxins, which cause damage to the intestinal mucosa leading to pseudo-membranous colitis. The organism colonizes the colon and then elaborates the toxins, which disrupt the mucosal barrier.
Choice B is incorrect as there is no preformed toxin ingested; the toxin is produced by the organism after colonization. Choice C is incorrect as Clostridium difficile does not invade and destroy the mucosa directly. Choice D is incorrect as the host immune response is a consequence of the toxin production, not the primary mechanism of disease.