Which of the following is NOT true of glucagon?

Correct Answer: D

Rationale: The correct answer is D because glucagon actually stimulates the liver to release glucose into the bloodstream, not store glucose as glycogen. Glucagon helps increase blood glucose levels by promoting the breakdown of glycogen into glucose, and it also promotes the use of fat and protein for energy when glucose levels are low. Choices A, B, and C are all true statements about glucagon, making them incorrect options in this context.

Correct Answer: B

Rationale: The correct answer is B: Hypothalamus. The hypothalamus controls the pituitary gland by releasing hormones that stimulate or inhibit pituitary hormone production. This relationship is known as the hypothalamic-pituitary axis. The hypothalamus is considered the master controller of the endocrine system, making it the correct choice. A: Thyroid - The thyroid gland is not directly responsible for controlling the pituitary gland. It is a separate endocrine gland that produces its own hormones. C: Pineal gland - The pineal gland primarily regulates the sleep-wake cycle and produces melatonin. It does not play a direct role in controlling the pituitary gland. D: None of the above - This is incorrect as the hypothalamus does indeed control the pituitary gland.

Correct Answer: B

Rationale: Rationale: - GLUT2 transporter on basolateral membrane transports glucose, galactose, and fructose. - SGLT-2 transporter on apical membrane co-transports glucose and galactose with Na. - Fructose absorption is via facilitated diffusion, not secondary active transport. - Insulin increases, not decreases, carbohydrate absorption.

Correct Answer: D

Rationale: The correct answer is D: acetylcholine. Acetylcholine directly stimulates parietal cells in the stomach to secrete hydrochloric acid. It binds to muscarinic receptors on parietal cells, leading to an increase in acid production. Prostaglandins (A) inhibit acid secretion, aspirin (B) can cause gastric irritation and ulcers, and vinegar (C) does not directly stimulate parietal cells.

Correct Answer: D

Rationale: The correct answer is D: submandibular glands. These glands produce the majority of salivary volume due to their larger size and higher rate of saliva production compared to other salivary glands. Submandibular glands secrete a combination of serous and mucous saliva, contributing to overall saliva volume. The lingual glands (choice A) are smaller and contribute a smaller amount of saliva. The sublingual glands (choice B) are also smaller and produce less saliva compared to the submandibular glands. The parotid glands (choice C) are the largest salivary glands but contribute a smaller volume of saliva compared to the submandibular glands.