Which of these digestive processes occurs in the mouth?

Correct Answer: C

Rationale: The correct answer is C: chemical digestion of starch. In the mouth, salivary glands secrete enzymes like amylase to break down starch into simpler sugars. This process initiates the digestion of carbohydrates. Mechanical digestion (Choice B) occurs in the mouth through chewing and mixing food with saliva, but it does not involve chemical breakdown. Chemical digestion of proteins (Choice A) primarily occurs in the stomach and small intestine with the help of enzymes like pepsin and trypsin. Choice D is incorrect because not all the processes listed occur in the mouth.

Correct Answer: A

Rationale: The correct answer is A: Mouth. In the mouth, salivary amylase is secreted, which starts breaking down carbohydrates into simpler sugars like maltose. This initial breakdown of carbohydrates through the enzyme amylase marks the beginning of chemical digestion. The stomach primarily digests proteins, not carbohydrates (eliminating option B). The small intestine is where most of the carbohydrate digestion and absorption occurs, but the process begins in the mouth (eliminating option C). The large intestine is responsible for absorbing water and electrolytes, not carbohydrate digestion (eliminating option D).

Correct Answer: D

Rationale: The correct answer is D because bile pigments are not needed for micelle formation. Micelles are formed by bile salts, which aid in the emulsification of fats. Choice A is incorrect as bile is primarily produced by the liver, not bile duct cells. Choice B is incorrect as primary bile acids are stored in the gall bladder, not secondary bile acids. Choice C is incorrect as secretin stimulates the release of pancreatic enzymes, not bile secretion.

Correct Answer: B

Rationale: The correct answer is B: Failure of digestion and absorption of proteins. Atrophy of gastric mucosal glands leads to decreased production of hydrochloric acid and pepsin, essential for protein digestion. This results in impaired breakdown of proteins, leading to failure of digestion and absorption. Choice A is incorrect as starch digestion primarily occurs in the mouth and small intestine. Choice C is incorrect because high gastrin levels are associated with increased acid production. Choice D is incorrect as secretin is not directly involved in protein digestion.

Correct Answer: A

Rationale: The correct answer is A: pyloric stenosis. In pyloric stenosis, there is hypertrophy of the pyloric sphincter muscle, leading to gastric outlet obstruction and projectile vomiting. This typically presents in infants around 2-6 weeks of age. Other choices (B) esophageal atresia presents with difficulty feeding and choking, (C) annular pancreas with duodenal obstruction, and (D) incomplete rotation of the gut with volvulus or obstruction due to malrotation. Pyloric stenosis is the most likely diagnosis in this scenario based on the age of the infant and the symptom of projectile vomiting.