The portion of the small intestine that is attached to the pylorus of the stomach is the

Correct Answer: A

Rationale: The duodenum connects to the pylorus.

Correct Answer: D

Rationale: The correct answer is D: oral cavity. The chemical digestion of carbohydrates begins in the mouth, specifically the oral cavity, where salivary amylase breaks down complex carbohydrates into simpler sugars. The enzyme amylase helps start the process of carbohydrate digestion before the food reaches the stomach. In contrast, the esophagus is not involved in digestion; the stomach primarily digests proteins with the help of gastric enzymes; and the duodenum is where further digestion of carbohydrates, fats, and proteins occurs with the help of pancreatic enzymes and bile.

Correct Answer: A

Rationale: The correct answer is A because assimilation involves the synthesis of new molecules from absorbed nutrients, requiring enzymes. Absorption, on the other hand, involves taking in nutrients through structures like microvilli and blood capillaries. Enzymes are essential for breaking down and building new molecules during assimilation. Blood capillaries and microvilli are necessary for absorption of dissolved nutrients, which are then utilized during assimilation. Therefore, enzymes are specifically needed for assimilation but not for absorption.

Correct Answer: B

Rationale: The correct answer is B: stomach. Gastric glands increase their secretory activity in response to the hormone gastrin released from the stomach. Gastrin stimulates the release of gastric acid and other digestive enzymes. The other choices, A: pancreas, C: liver, and D: duodenum, do not release hormones directly involved in regulating gastric gland secretory activity. Pancreas secretes insulin and glucagon, liver secretes bile, and duodenum secretes hormones like secretin and cholecystokinin, but none of these directly influence gastric gland secretions.

Correct Answer: C

Rationale: The correct answer is C: bolus. A bolus refers to the rounded mass of food that is formed in the mouth and swallowed, moving through the esophagus to the stomach. This process is essential for digestion to occur properly. Choice A, sphincter, is incorrect as it is a muscular ring that regulates the flow of substances. Choice B, cannula, is a tube used for medical purposes, not related to food digestion. Choice D, chyme, is the partially digested food mixed with stomach acid, not the initial mass of food swallowed.