Nokea
What substance activates pepsinogen to pepsin?
- A. Bile
- B. Gastrin
- C. Secretin
- D. Hydrochloric acid
Correct Answer: D
Rationale: The correct answer is D: Hydrochloric acid. Hydrochloric acid in the stomach plays a crucial role in converting pepsinogen into its active form, pepsin, which is necessary for digesting proteins. Bile (Choice A) is involved in the emulsification of fats, not in the activation of pepsinogen. Gastrin (Choice B) is a hormone that stimulates the secretion of gastric acid but does not directly activate pepsinogen. Secretin (Choice C) is a hormone that regulates the pH of the duodenum but is not responsible for the activation of pepsinogen.
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Where does the absorption of most nutrients occur?
- A. Large intestine.
- B. Small intestine.
- C. Stomach.
- D. Mouth.
Correct Answer: B
Rationale: The absorption of most nutrients occurs in the small intestine. This is where digested food is broken down further and absorbed into the bloodstream through the intestinal walls. The large intestine primarily absorbs water and electrolytes, while the stomach mainly aids in digestion by breaking down food with gastric juices. The mouth is responsible for the initial mechanical breakdown of food through chewing and the enzymatic action of saliva, but absorption does not occur there.
After ingested food is mixed and churned with gastric secretions, the resulting semifluid mass is called:
- A. a bolus.
- B. chyme.
- C. rennin.
- D. glycogen.
Correct Answer: B
Rationale: The correct answer is B: chyme. Chyme is the partially digested food that forms a semifluid mass after mixing with gastric juices. A is incorrect because a bolus refers to a rounded mass of food ready to be swallowed. C, rennin, is an enzyme involved in the digestion of milk proteins and not the term for the semifluid mass after food mixing with gastric secretions. D, glycogen, is a form of stored glucose in the body and is not the term used to describe the partially digested food mass in the stomach.
Regurgitation or reflux of acidic stomach contents back into the esophagus is known as:
- A. hiatal hernia.
- B. diverticulitis.
- C. gastroenteritis.
- D. gastroesophageal reflux disease.
Correct Answer: D
Rationale: The correct answer is D: gastroesophageal reflux disease (GERD). GERD occurs when stomach acid flows back into the esophagus, causing symptoms like heartburn and regurgitation. Choice A, hiatal hernia, is a condition where part of the stomach pushes up into the chest through an opening in the diaphragm. Choice B, diverticulitis, is inflammation or infection of small pouches that can form in the lining of the digestive system. Choice C, gastroenteritis, is inflammation of the stomach and intestines typically caused by a viral or bacterial infection. Therefore, only choice D accurately describes the regurgitation or reflux of acidic stomach contents back into the esophagus.
Why are bacteria found in the colon important?
- A. synthesize important vitamins.
- B. complete the process of absorption.
- C. synthesize some minerals.
- D. finish the process of digestion.
Correct Answer: A
Rationale: Bacteria found in the colon are important because they synthesize important vitamins, such as vitamin K. This aids in the body's overall health and functioning. Choice B is incorrect because absorption primarily occurs in the small intestine, not the colon. Choice C is incorrect as the synthesis of minerals is not a primary function of colon bacteria. Choice D is incorrect as the digestion process mainly occurs in the stomach and small intestine.
Where does gluconeogenesis occur?
- A. Muscles.
- B. Pancreas.
- C. Liver.
- D. Spleen.
Correct Answer: C
Rationale: Gluconeogenesis mainly occurs in the liver. It is a process where glucose is synthesized from non-carbohydrate sources such as amino acids and glycerol. The liver is the primary site for gluconeogenesis due to the presence of key enzymes and substrates required for this process. Muscles do not play a significant role in gluconeogenesis, making choice A incorrect. The pancreas is involved in the regulation of blood sugar levels through insulin and glucagon but is not the primary site for gluconeogenesis, so choice B is incorrect. The spleen is not a major organ involved in glucose metabolism, making choice D incorrect.