Chemical digestion of protein begins in the:

Correct Answer: B

Rationale: The correct answer is B: stomach. Chemical digestion of protein begins in the stomach where the enzyme pepsin breaks down proteins into peptides. The stomach's acidic environment activates pepsinogen to pepsin. In contrast, the mouth primarily performs mechanical digestion through chewing, and the small intestine is where further breakdown and absorption of nutrients occur. The large intestine mainly absorbs water and electrolytes, with minimal involvement in protein digestion.

Correct Answer: B

Rationale: The correct answer is B: Keep the head of your bed elevated on blocks. Elevating the head of the bed can help prevent stomach acid from flowing back into the esophagus during sleep, reducing nighttime symptoms of GERD. This position helps gravity keep the acid in the stomach. A: Peppermint tea may actually worsen GERD symptoms as it can relax the lower esophageal sphincter, allowing acid to reflux back into the esophagus. C: Avoiding eating between meals will not reduce acid secretion and may even lead to larger meals, which can trigger reflux symptoms. D: Vigorous physical activities can worsen GERD symptoms by increasing intra-abdominal pressure, pushing stomach contents back up into the esophagus. In summary, the correct answer is B because it directly addresses a practical measure to alleviate GERD symptoms during sleep, while the other choices do not effectively manage the condition.

Correct Answer: A

Rationale: The correct answer is A: chief cells. Chief cells are responsible for secreting gastric enzymes, such as pepsinogen, in the stomach. These enzymes play a crucial role in breaking down proteins during digestion. Goblet cells (B) secrete mucus, parietal cells (C) secrete hydrochloric acid, and oxyntic cells (D) are another term for parietal cells. Therefore, the correct choice is A as chief cells specifically produce gastric enzymes.

Correct Answer: A

Rationale: The correct answer is A: liver. The liver produces and secretes bile which helps in the digestion of fats. B: gallbladder stores and concentrates bile produced by the liver. C: pancreas secretes digestive enzymes but not bile. D: duodenum is the first part of the small intestine where bile is released to aid in digestion.

Correct Answer: B

Rationale: The correct answer is B: chylomicrons. Chylomicrons are lipoprotein particles that transport dietary lipids (including fatty acids and glycerol) from the small intestine to the liver or muscle cells for metabolism. When chylomicrons reach the liver or muscles, lipoprotein lipase breaks them down, releasing fatty acids and glycerol for energy production or storage. Now, let's analyze why the other choices are incorrect: A: Micelles are small lipid droplets formed in the small intestine to aid in lipid digestion and absorption, but they do not release fatty acids and glycerol when broken down. C: Lacteals are lymphatic vessels in the small intestine that absorb dietary fats, but they do not release fatty acids and glycerol. D: Lipoproteins are involved in transporting lipids in the bloodstream but do not release fatty acids and glycerol when broken down.