Nokea
The muscles of the esophagus squeeze the food downward using the process of:
- A. gravity
- B. peristalsis
- C. rugae
- D. chyme
Correct Answer: B
Rationale: The correct answer is B: peristalsis. Peristalsis is the coordinated, rhythmic muscle contractions that propel food through the esophagus and digestive tract. This process helps move food downward towards the stomach. Gravity (choice A) is not the primary mechanism for moving food through the esophagus. Rugae (choice C) refers to folds in the stomach lining, not muscle action in the esophagus. Chyme (choice D) is the partially digested food mixed with stomach acids and enzymes, not a process of moving food down the esophagus. Therefore, peristalsis is the correct answer as it accurately describes the muscle action involved in pushing food downward through the esophagus.
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What is the role of pepsin in digestion?
- A. Digesting carbohydrates
- B. Digesting fats
- C. Digesting proteins
- D. Digesting nucleic acids
Correct Answer: C
Rationale: The correct answer is C: Digesting proteins. Pepsin is a digestive enzyme produced in the stomach that specifically breaks down proteins into smaller peptides. It works optimally in acidic environments, aiding in the digestion of proteins consumed in the diet. The other choices are incorrect because pepsin does not play a role in digesting carbohydrates (A), fats (B), or nucleic acids (D). Carbohydrates are primarily broken down by enzymes like amylase, fats by lipase, and nucleic acids by nucleases. Thus, pepsin's main function is to digest proteins in the stomach.
What contributes to increased protein-calorie needs?
- A. Surgery
- B. Vegan diet
- C. Lowered temperature
- D. Cultural or religious beliefs
Correct Answer: A
Rationale: The correct answer is A: Surgery. Surgery increases protein-calorie needs due to the body's increased demand for nutrients to support healing and recovery. The body requires more protein and calories to repair tissues and maintain immune function post-surgery.
Choice B: A vegan diet does not necessarily contribute to increased protein-calorie needs as it is possible to meet nutritional requirements with proper planning.
Choice C: Lowered temperature does not directly affect protein-calorie needs.
Choice D: Cultural or religious beliefs do not inherently increase protein-calorie needs, as dietary choices can still meet nutritional requirements.
Secretin and cholecystokinin are secreted in
- A. pyloric region
- B. Ileum
- C. duodenum
- D. Oesophagus
Correct Answer: C
Rationale: The correct answer is C, duodenum. Secretin and cholecystokinin are hormones secreted by the duodenal mucosa in response to the presence of acidic chyme from the stomach entering the duodenum. Secretin stimulates the pancreas to release bicarbonate to neutralize the acidic chyme, while cholecystokinin stimulates the gallbladder to release bile to aid in digestion. Choices A (pyloric region), B (Ileum), and D (Oesophagus) are incorrect because secretin and cholecystokinin are not secreted in these regions of the gastrointestinal tract.
What role do the teeth play in digestion?
- A. chemical digestion
- B. mechanical digestion
- C. enzymatic digestion
- D. absorption
Correct Answer: B
Rationale: The correct answer is B: mechanical digestion. Teeth play a crucial role in breaking down food into smaller pieces through physical chewing, which is a form of mechanical digestion. This process increases the surface area of food particles, making it easier for enzymes to further break down nutrients during chemical digestion in the stomach and intestines. Choice A (chemical digestion) is incorrect because teeth do not directly participate in chemical breakdown of food. Choice C (enzymatic digestion) is incorrect as enzymes are not produced by teeth but by salivary glands and other digestive organs. Choice D (absorption) is incorrect as teeth are not involved in absorbing nutrients; absorption primarily occurs in the small intestine.
Which of the following cells in the stomach secrete pepsinogen?
- A. parietal cells
- B. chief cells
- C. mucous neck cells
- D. enteroendocrine cells
Correct Answer: B
Rationale: The correct answer is B: chief cells. Chief cells are responsible for secreting pepsinogen in the stomach. Pepsinogen is an inactive form of pepsin, which is an enzyme that helps in protein digestion. Parietal cells secrete hydrochloric acid, not pepsinogen. Mucous neck cells secrete mucus to protect the stomach lining. Enteroendocrine cells secrete hormones like gastrin, but not pepsinogen. Therefore, the correct answer is B as chief cells are the specific cells that secrete pepsinogen in the stomach.