Pituitary Gland, Which is Also the Master Endocrine Gland Is Controlled by Which of the Following?

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: 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.

Correct Answer: B

Rationale: The correct answer is B because insulin deficiency leads to increased gluconeogenesis due to the lack of inhibition on glucose production. Choice A is incorrect as insulin binds to GLUT 4 receptors, not GLUT 1-5. Choice C is wrong because insulin's half-life is only a few minutes. Choice D is also inaccurate as insulin is secreted by pancreatic beta cells, not A cells.

Correct Answer: B

Rationale: Step-by-step rationale for the correct answer (B): 1. During starvation, the body shifts to using ketoacids derived from fats for fuel. 2. The brain and other tissues can utilize these ketoacids. 3. This process helps to spare protein and prevent muscle breakdown. 4. Therefore, choice B is correct as ketoacids play a crucial role in providing energy during starvation. Summary of why other choices are incorrect: A: Glycogen stores are depleted within 24 hours, not 48 hours. C: Hypoglycemia during starvation does not have a protein sparing effect. D: The average time until death from starvation is typically much shorter than 40 days.