A patient who undergoes the following operation will NOT survive without parenteral feeding:

Correct Answer: B

Rationale: The correct answer is B: Total gastrectomy. This operation involves complete removal of the stomach, leading to the inability to digest food. Without a stomach, essential nutrients cannot be absorbed, necessitating parenteral feeding. A: Total oesophagectomy - Although the esophagus is important for swallowing, parenteral feeding can sustain life without it. C: Right hepatic lobectomy - The liver has regenerative capacity and can compensate for the loss of a lobe. D: Total oroclocolectomy - This operation removes the entire colon, but parenteral feeding can still provide nutrition. In summary, total gastrectomy results in the loss of the major organ responsible for digestion and nutrient absorption, requiring parenteral feeding for survival.

Correct Answer: B

Rationale: The correct answer is B: Hirschsprung's disease. The absence of ganglion cells in the distal colon is a key diagnostic feature of Hirschsprung's disease. Ganglion cells are essential for coordinated contractions of the colon. In congenital pyloric stenosis, the issue lies in the pylorus, not the colon, so ganglion cells are not relevant. Choice C is incorrect because congenital pyloric stenosis does not involve ganglion cells. Choice D is also incorrect as Hirschsprung's disease does indeed involve the absence of ganglion cells.

Correct Answer: C

Rationale: The correct answer is C because carcinoma of the esophagus often spreads locally, making complete removal difficult. This local spread can involve nearby structures, leading to a poor prognosis. Metastases to the liver or lung (choice A) typically occur later in the disease course, not before diagnosis. While some esophageal tumors may be challenging to access surgically (choice B), this alone does not explain the poor prognosis. Esophageal cancer can respond to radiotherapy (choice D), so radioresistance is not the primary reason for the poor prognosis. In summary, the local spread preventing complete removal is the key factor contributing to the poor prognosis in esophageal carcinoma.

Correct Answer: B

Rationale: The correct answer is B because the buccal phase of swallowing is a voluntary process where the tongue moves the bolus of food towards the back of the mouth to initiate swallowing. This phase is under conscious control and initiates the swallowing reflex. Choice A is incorrect because the buccal phase is voluntary, not involuntary. Choice C is incorrect because the bolus is moved towards the back of the mouth, not rolled over the front of the tongue. Choice D is incorrect because the movement of food from the pharynx to the esophagus occurs during the pharyngeal phase of swallowing, not the buccal phase.

Correct Answer: D

Rationale: The correct answer is D: Submucosa. The submucosa is the layer of tissue beneath the mucosa in the gastrointestinal tract. It contains blood vessels, nerves, and glands that support the mucosa. Muscularis externa (A) is the layer of smooth muscle responsible for peristalsis. Circular muscle (B) is a type of muscle fiber found within the muscularis externa. Serosa (C) is the outermost layer of the digestive tract that provides protection and secretes fluid. The submucosa (D) is the correct answer because it is the layer directly beneath the mucosa and plays a crucial role in supporting and nourishing the mucosal layer.