Drug overdosage in parkinsonian patients may cause pronounced gastrointestinal side-effects related to:

Correct Answer: A

Rationale: The correct answer is A: Bromocriptine. Bromocriptine is a dopamine agonist used in Parkinson's disease treatment. Drug overdosage can lead to pronounced gastrointestinal side-effects due to its action on dopamine receptors in the gastrointestinal tract. Co-beneldopa (B) is a combination drug of levodopa and carbidopa, primarily affecting the central nervous system, not causing significant gastrointestinal issues. Amantadine (C) is an antiviral and anti-Parkinson agent with minimal gastrointestinal side effects. Selegeline (D) is a monoamine oxidase-B inhibitor, typically causing side effects like insomnia and dizziness rather than pronounced gastrointestinal issues.

Correct Answer: D

Rationale: Correct Answer: D Rationale: 1. Digestion begins in the mouth with mechanical and chemical breakdown of food by chewing and saliva. 2. Chewing helps break down food into smaller pieces, increasing surface area for enzymes to act upon. 3. Saliva contains enzymes that start breaking down starches into sugars. 4. Chewing mixes food with saliva, aiding in the initial digestion process. 5. The statement that "digestive juices can react more easily with the food when chewed" is incorrect. Digestive juices act after food passes through the mouth and into the stomach and intestines, not in the mouth.

Correct Answer: B

Rationale: Step-by-step rationale: 1. The liver does not manufacture insulin; this function is carried out by the pancreas. 2. Storing food is a function of the liver (choice A). 3. Producing digestive juices is a function of the liver (choice C). 4. The liver has the ability to regenerate and heal itself when damaged (choice D). Summary: Choice B is incorrect because the liver does not manufacture insulin; the correct answer is B. Choices A, C, and D are incorrect as they are all functions of the liver.

Correct Answer: B

Rationale: The correct answer is B: stomach to the esophagus. The cardiac sphincter is located between the esophagus and the stomach. Its main function is to prevent the backflow of stomach contents, including acid chyme, from the stomach back into the esophagus. This helps to protect the delicate lining of the esophagus from damage due to the acidic environment of the stomach. Explanation for other choices: A: The esophagus does not connect to the mouth, so backflow from the esophagus to the mouth is not a concern. C: The duodenum is the first part of the small intestine and is located after the stomach, so backflow to the stomach is not controlled by the cardiac sphincter. D: The colon is part of the large intestine and is not directly connected to the small intestine, so backflow from the colon to the small intestine is not relevant to the function of the cardiac sphincter.

Correct Answer: C

Rationale: The correct answer is C: mouth. Starch digestion begins in the mouth with the action of salivary amylase, an enzyme that breaks down starch into maltose. This process initiates the breakdown of complex carbohydrates into simpler sugars. The stomach (A) primarily digests proteins, the small intestine (B) further breaks down carbohydrates, proteins, and fats, and the esophagus (D) is a passageway for food to travel from the mouth to the stomach. Hence, the mouth is where the digestion of starch begins due to the presence of salivary amylase.