Nokea
The low pH of the stomach activates enzymes that digest ______ while inactivating enzymes that digest ______.
- A. lipids; proteins
- B. proteins; starch
- C. starch; proteins
- D. nucleic acids; starch
Correct Answer: B
Rationale: The correct answer is B because the low pH of the stomach activates pepsin, an enzyme that digests proteins, while inactivating salivary amylase, an enzyme that digests starch. Pepsin works optimally in an acidic environment, breaking down proteins into peptides. Salivary amylase, on the other hand, works best at a neutral pH and is denatured in the acidic stomach, leading to its inactivation. Choices A, C, and D are incorrect because lipids are primarily digested in the small intestine, and nucleic acids are not directly affected by the stomach's pH.
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During a routine screening colonoscopy on a 56-year-old patient, a rectosigmoidal polyp was identified and remove The patient asks the nurse if his risk for colon cancer is increased because of the polyp. What is the best response by the nurse?
- A. It is very rare for polyps to become malignant but you should continue to have routine colonoscopies.'
- B. Individuals with polyps have a 100% lifetime risk of developing colorectal cancer and at an earlier age than those without polyps.'
- C. All polyps are abnormal and should be removed but the risk for cancer depends on the type and if malignant changes are present.'
- D. All polyps are premalignant and a source of most colon cancer. You will need to have a colonoscopy every 6 months to check for new polyps.'
Correct Answer: C
Rationale: Rationale:
1. Choice C is correct because it acknowledges that all polyps are abnormal and should be removed, but the risk for cancer depends on the type and presence of malignant changes.
2. This response is accurate as not all polyps become cancerous, and the risk varies depending on the specific characteristics of the polyp.
3. It also emphasizes the importance of removing polyps and monitoring for any signs of malignancy, aligning with best practice guidelines for colon cancer prevention.
4. In contrast, choices A, B, and D provide misleading information by either downplaying or exaggerating the risk associated with polyps, which can lead to unnecessary anxiety or complacency in the patient.
The submucosa of the GIT
- A. Is important for protection
- B. Helps with absorption and secretion
- C. Contains an outer and inner layer
- D. Is between the serosa and muscularis externa
Correct Answer: B
Rationale: The submucosa of the GIT is rich in blood vessels, nerves, and lymphatic vessels, aiding in absorption and secretion of nutrients and fluids. The submucosa is not primarily responsible for protection (choice A). It does not contain distinct outer and inner layers (choice C). The submucosa is located between the mucosa and muscularis externa, not the serosa (choice D). Therefore, the correct answer is B as it aligns with the known functions and characteristics of the submucosa.
Which enzyme is primarily responsible for the digestion of carbohydrates in the small intestine?
- A. Pepsin
- B. Lipase
- C. Amylase
- D. Trypsin
Correct Answer: C
Rationale: The correct answer is C: Amylase. Amylase is primarily responsible for digesting carbohydrates in the small intestine. It breaks down complex carbohydrates into simpler sugars like maltose and glucose. Pepsin (A) is a stomach enzyme that breaks down proteins, not carbohydrates. Lipase (B) digests fats, not carbohydrates. Trypsin (D) is a pancreatic enzyme that digests proteins, not carbohydrates. Amylase is the only enzyme among the choices that specifically targets carbohydrates for digestion in the small intestine.
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).
Cholecystokinin (CCK):
- A. is secreted by the gastric antrum.
- B. is inhibited by excess fat in the duodenum.
- C. Stimulates pancreatic acini to secrete enzymes.
- D. inhibits gallbladder evacuation.
Correct Answer: C
Rationale: The correct answer is C because Cholecystokinin (CCK) is a hormone secreted by the duodenum in response to the presence of fats and proteins. It stimulates the pancreatic acini to secrete digestive enzymes such as lipase and proteases. This helps in the digestion and absorption of fats and proteins. The other choices are incorrect because A is false - CCK is secreted by the duodenum, not the gastric antrum. B is false - CCK is actually stimulated by the presence of fats in the duodenum. D is false - CCK actually stimulates gallbladder contraction to release bile, aiding in fat digestion.