Which of the following organs has 3 layers of smooth muscle in its muscularis externa?

Correct Answer: C

Rationale: The correct answer is C: stomach. The stomach has 3 layers of smooth muscle in its muscularis externa, known as the inner oblique, middle circular, and outer longitudinal layers. These layers help in the mechanical digestion of food by churning and mixing it with gastric juices. Rationale: 1. Small intestine (A): The small intestine has 2 layers of smooth muscle in its muscularis externa, not 3. 2. Esophagus (B): The esophagus has 2 layers of smooth muscle in its muscularis externa, not 3. 3. Large intestine (D): The large intestine has 2 layers of smooth muscle in its muscularis externa, not 3.

Correct Answer: C

Rationale: The correct answer is C, an anticholinergic medication. Anticholinergics inhibit the action of acetylcholine, which is responsible for stimulating intestinal motility. By blocking this stimulation, anticholinergic medications can effectively immobilize the intestines during surgery. Choice A, cholinergic medication, would have the opposite effect by increasing intestinal activity. Choice B, antiadrenergic medication, does not directly affect intestinal motility. Choice D is incorrect as both cholinergic and anticholinergic medications cannot be effective at immobilizing the intestines simultaneously.

Correct Answer: A

Rationale: The correct answer is A: esophagus. The esophagus is a muscular tube that connects the mouth to the stomach, allowing food to pass through for digestion. It does not have a role in breathing (like the trachea), nor is it part of the upper respiratory tract (nasopharynx). The epiglottis is a flap that covers the trachea during swallowing to prevent food from entering the airway, but it doesn't transport food to the stomach. Therefore, the esophagus is the correct answer as it specifically functions to pass food from the mouth to the stomach.

Correct Answer: B

Rationale: The correct answer is B: Gastro-oesophageal reflux disease. This is known as the classic presentation of pericarditis. The pain worsens when lying flat due to increased pressure on the inflamed pericardium, and improves when leaning forward, reducing pressure. Angina (A) typically presents with exertional chest pain, not worsened by lying flat. Myocardial infarction (C) presents with crushing chest pain, not positional like pericarditis. Pulmonary embolism (D) presents with sudden onset dyspnea and chest pain, not exacerbated by lying flat.

Correct Answer: D

Rationale: The most likely diagnosis for the 50-year-old man with swollen ankles, raised jugular venous pressure, and a history of chronic obstructive pulmonary disease is right heart failure (Choice D). In this case, the patient's symptoms suggest signs of right-sided heart failure, such as peripheral edema and jugular venous distention. Chronic obstructive pulmonary disease can lead to pulmonary hypertension, causing right heart failure. Asthma (Choice A) is primarily a respiratory condition, not typically associated with jugular venous distention or peripheral edema. Congestive heart failure (Choice B) usually presents with features of pulmonary edema and bilateral lower extremity edema, rather than isolated right-sided heart failure. Constrictive pericarditis (Choice C) may present with jugular venous distention, but it is less common compared to right heart failure in a patient with a history of chronic obstructive pulmonary disease.