Stimulation of the parasympathetic neurons in the GI tract from Auerbach's or myenteric plexus will cause

Correct Answer: D

Rationale: Stimulation of parasympathetic neurons in the GI tract from Auerbach's or myenteric plexus leads to the release of acetylcholine, which enhances GI motility and peristalsis. This is because acetylcholine acts on smooth muscle and stimulates contractions, promoting movement of food through the GI tract. Therefore, the correct answer is D. A: Inhibition of local secretions is incorrect as parasympathetic stimulation usually enhances glandular secretions in the GI tract. B: Inhibition of peristalsis is incorrect because parasympathetic stimulation typically increases peristalsis. C: Stimulation of local secretions is incorrect as parasympathetic stimulation usually promotes secretion but does not inhibit it.

Correct Answer: B

Rationale: The correct answer is B: rugae. Rugae are large folds in the tunica submucosa and mucosa of the stomach that allow for expansion when the stomach is full. Epiploic appendages (A) are fatty projections on the serosa of the large intestine. Plicae circulares (C) are circular folds in the small intestine for increasing surface area. Villi (D) are finger-like projections in the small intestine for absorption. Rugae specifically refer to the folds in the stomach lining, making them the correct answer.

Correct Answer: C

Rationale: Granular cells, also known as Paneth cells, produce antimicrobial peptides to protect the intestinal epithelium from bacteria. These peptides have antimicrobial properties that help prevent bacterial overgrowth and maintain intestinal homeostasis. Absorptive cells are primarily responsible for nutrient absorption, while goblet cells secrete mucus for lubrication. Endocrine cells produce hormones that regulate various physiological processes. Therefore, the correct answer is C, as granular cells play a direct role in protecting the intestinal epithelium from bacteria.

Correct Answer: D

Rationale: The correct answer is D: chymotrypsin. Chymotrypsin is not part of the enzymatic component of pancreatic juice. Pancreatic juice contains amylase for carbohydrate digestion, lipase for fat digestion, and nucleases for nucleic acid digestion. Chymotrypsin is produced in the pancreas but is not secreted directly into the pancreatic juice. It is released in an inactive form that is activated in the small intestine. Therefore, chymotrypsin is not directly involved in the initial breakdown of nutrients in the pancreatic juice.

Correct Answer: D

Rationale: The correct answer is D: high-density lipoprotein (HDL). HDL is known to have a higher proportion of protein compared to other lipoproteins. In this case, with 45% protein content, it aligns with the typical composition of HDL. HDL is responsible for transporting cholesterol from peripheral tissues back to the liver for excretion, making it crucial for maintaining cardiovascular health. A: Micelle is incorrect as it is a single-layered structure formed by amphipathic molecules in a specific environment like bile salts in the intestines. B: Chylomicron is incorrect as it is primarily composed of triglycerides and is responsible for transporting dietary lipids. C: Low-density lipoprotein (LDL) is incorrect as it typically has higher cholesterol content compared to HDL and is known as "bad cholesterol" due to its role in depositing cholesterol in arteries.