An 8-month-old boy is reported by his mother to have had several episodes of 'colic' and she has noticed blood in his stools. Your examination is negative except for slight abdominal tenderness and moderate anemiWhich of the following is most likely?

Correct Answer: C

Rationale: The correct answer is C: Meckel's diverticulum. Meckel's diverticulum is a congenital outpouching of the small intestine that may contain gastric or pancreatic tissue, leading to ulceration and bleeding. In this case, the presence of blood in the stools along with abdominal tenderness and anemia is highly suggestive of Meckel's diverticulum. Pyloric stenosis typically presents with non-bloody projectile vomiting in a male infant. Intestinal atresia usually presents with bilious vomiting and abdominal distension in a newborn. Hirschsprung's disease presents with chronic constipation and failure to pass meconium shortly after birth. Therefore, based on the symptoms and age of the child, Meckel's diverticulum is the most likely diagnosis.

Correct Answer: B

Rationale: The correct answer is B: Helps in food absorption. Chewing primarily aids in food breakdown into smaller particles for easier digestion. Chewing does not directly contribute to food absorption, as absorption mainly occurs in the small intestine. A: Sense of satiety is correct, as chewing helps signal fullness to the brain. C: Helps in food digestion is correct, as chewing starts the mechanical breakdown process. D: Increase salivary secretion is incorrect, as chewing stimulates saliva production to aid in digestion.

Correct Answer: A

Rationale: Rationale for Correct Answer A: - Parietal cells in gastric glands secrete gastric acid in response to hormonal stimulation, primarily gastrin. - Gastrin is released in response to the presence of food in the stomach, stimulating acid secretion. - This process is essential for digestion and maintaining the acidity of the stomach environment. Summary of Incorrect Choices: - B: Most of the secretion of acid and pepsinogen occurs during the gastric (not intestinal) phase. - D: Gastric secretion begins before food enters the stomach, as cephalic phase responses can initiate acid secretion.

Correct Answer: A

Rationale: The correct answer is A: Chyme. This term refers to the semi-solid mixture of food and digestive juices that is formed in the stomach through the process of digestion. The stomach mixes food with gastric juices to create chyme, which is then passed to the small intestine for further digestion and absorption of nutrients. B: Bolus is incorrect as it refers to the compact mass of food that is swallowed and travels through the esophagus to reach the stomach. C: Feces is incorrect as it is the solid waste material that is formed in the large intestine and expelled from the body. D: None of the above is incorrect as the term "chyme" accurately describes the semi-solid mixture formed in the stomach during digestion.

Correct Answer: C

Rationale: The correct answer is C: Unintended weight loss. In older adults, unintended weight loss can be a sign of underlying health issues such as malnutrition, chronic diseases, or even cancer. It is a significant concern as it may indicate a decline in overall health and increase the risk of complications. Decreased appetite (choice A) and occasional indigestion (choice B) are common in older adults but may not necessarily be as alarming as unintended weight loss. Difficulty chewing food (choice D) could also contribute to weight loss but is not as concerning as the weight loss itself, which could have more serious implications.