What are the small, fingerlike projections into the intestinal lumen called?
- A. Villi
- B. Goblets
- C. Lacteals
- D. Polyps
Correct Answer: A
Rationale: The correct answer is A: Villi. Villi are small fingerlike projections in the intestine that increase the surface area for nutrient absorption. Goblets (choice B) are mucus-secreting cells in the intestines. Lacteals (choice C) are lymphatic vessels in the small intestine that absorb dietary fats. Polyps (choice D) are abnormal tissue growths.
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Ketones are produced when:
- A. carbohydrate stores are depleted.
- B. excess protein is consumed.
- C. protein stores are depleted.
- D. fat stores are depleted.
Correct Answer: A
Rationale: Ketones are produced when the body uses fat for energy due to the depletion of carbohydrate stores. When carbohydrate stores are depleted, the body turns to fat as its primary source of energy, leading to the production of ketones. Excess protein consumption does not directly lead to ketone production. Similarly, the depletion of protein stores or fat stores is not directly related to the production of ketones.
The interrelated network of nerves within the gastrointestinal wall that regulates its muscular action is known as the:
- A. gastric nerve plexus.
- B. biliary nerve plexus.
- C. intramural nerve plexus.
- D. intestinal nerve plexus.
Correct Answer: C
Rationale: The correct answer is C - intramural nerve plexus. This network of nerves regulates the muscular movements within the gastrointestinal wall. The gastric nerve plexus (choice A) specifically relates to the stomach, not the entire gastrointestinal tract. The biliary nerve plexus (choice B) is associated with the bile ducts and gallbladder, not the regulation of muscular action. The intestinal nerve plexus (choice D) is a general term that doesn't specifically refer to the network of nerves within the gastrointestinal wall.
How many different amino acids make up human proteins?
- A. 9
- B. 13
- C. 15
- D. 20
Correct Answer: D
Rationale: The correct answer is D: 20. There are 20 different amino acids that combine to form proteins in the human body. Each amino acid has a unique side chain that determines its properties. Choices A, B, and C are incorrect as they do not represent the total number of different amino acids found in human proteins.
Which hormone stimulates the gallbladder to contract?
- A. Secretin.
- B. Cholecystokinin (CCK).
- C. Gastrin.
- D. Gastric inhibitory polypeptide (GIP).
Correct Answer: B
Rationale: Cholecystokinin (CCK) is the hormone responsible for stimulating the gallbladder to contract and release bile into the small intestine. Secretin primarily acts on the pancreas to stimulate the secretion of bicarbonate-rich fluid. Gastrin functions in the stimulation of gastric acid secretion, while Gastric inhibitory polypeptide (GIP) plays a role in inhibiting gastric acid secretion and stimulating insulin release.
The valve that controls the passage of chyme from the small intestine into the cecum is called the:
- A. ileocecal valve.
- B. pyloric valve.
- C. cardiac valve.
- D. hepatic valve.
Correct Answer: A
Rationale: The correct answer is A: ileocecal valve. The ileocecal valve is located between the small intestine and the cecum, controlling the passage of chyme. The pyloric valve (choice B) is located between the stomach and the small intestine, regulating the passage of food from the stomach to the small intestine. The cardiac valve (choice C) refers to the valve between the esophagus and the stomach. The hepatic valve (choice D) is not a correct term related to the passage of chyme from the small intestine into the cecum.