Which of the following is NOT related to adrenal medulla structure and function?
- A. Inner portion of adrenal gland.
- B. Controlled by the nervous system.
- C. Regulates levels of glucose and minerals in the blood.
- D. Produces epinephrine and norepinephrine.
Correct Answer: C
Rationale: The correct answer is C: Regulates levels of glucose and minerals in the blood. The adrenal medulla is responsible for producing epinephrine and norepinephrine, not regulating blood glucose and minerals. The inner portion of the adrenal gland refers to the adrenal medulla. It is controlled by the nervous system, specifically the sympathetic nervous system. Epinephrine and norepinephrine produced by the adrenal medulla are involved in the body's fight-or-flight response, not in regulating blood glucose and minerals. Therefore, choice C is the correct answer as it is not related to adrenal medulla structure and function.
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Most hormones of the endocrine system are regulated by a .
- A. hormone-gene complex
- B. hormone-receptor complex
- C. negative feedback mechanism
- D. positive feedback mechanism
Correct Answer: C
Rationale: The correct answer is C: negative feedback mechanism. This is because the majority of hormones in the endocrine system are regulated by a feedback loop that maintains homeostasis by inhibiting further hormone production when levels are too high and stimulating production when levels are too low. This negative feedback mechanism ensures that hormone levels remain within a narrow range.
A: hormone-gene complex is incorrect as hormones are not primarily regulated by direct interactions with genes.
B: hormone-receptor complex is incorrect as receptors are involved in hormone action, not regulation.
D: positive feedback mechanism is incorrect as it would lead to an amplification of hormone production, which is not typically seen in the endocrine system to maintain stability.
Insulin:
- A. binds to GLUT 1-5 receptors in the peripheral tissues
- B. deficiency results in increased gluconeogenesis
- C. has a plasma half-life of 2-3 hours
- D. is secreted by the pancreatic A cells
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.
Intravenous administration of epinephrine to a patient results in a severe decrease in diastolic pressure and an increase in cardiac output. Which of the following drugs might the patient have previously taken that could account for this unexpected effect?
- A. Propranolol
- B. Atropine
- C. Phenylephrine
- D. Prazosin
Correct Answer: D
Rationale: The correct answer is D: Prazosin. Prazosin is an alpha-1 adrenergic receptor antagonist, which blocks the vasoconstrictor effect of catecholamines like epinephrine, leading to vasodilation and a decrease in diastolic pressure. The unexpected effect of a decrease in diastolic pressure and an increase in cardiac output after epinephrine administration suggests that the patient might have taken a drug that blocks alpha-1 receptors. Propranolol (A) is a beta-blocker, which would not cause this effect. Atropine (B) is a muscarinic receptor antagonist and would not explain the observed effects. Phenylephrine (C) is an alpha-1 agonist, so it would not result in the described response. Therefore, Prazosin (D) is the most likely drug the patient previously took to account for the unexpected effects of epinephrine administration.
Which hormone is produced by the adrenal cortex?
- A. Insulin
- B. Epinephrine
- C. Aldosterone
- D. Glucagon
Correct Answer: C
Rationale: The correct answer is C: Aldosterone. The adrenal cortex produces aldosterone, which helps regulate blood pressure and electrolyte balance. Insulin (A) is produced by the pancreas, epinephrine (B) is produced by the adrenal medulla, and glucagon (D) is produced by the pancreas. Aldosterone is the only hormone produced by the adrenal cortex among the options provided, making it the correct answer.
The small intestine runs from the stomach to the large intestine. It has three parts. Starting at the stomach, in which order do they occur?
- A. Ileum, duodenum, jejunum
- B. Jejunum, duodenum, ileum
- C. Duodenum, ileum, jejunum
- D. Duodenum, jejunum, ileum
Correct Answer: D
Rationale: The correct order is D: Duodenum, jejunum, ileum. The duodenum is the first part of the small intestine connected to the stomach for digestion. Next is the jejunum, where most of the nutrients are absorbed. Lastly, the ileum completes the absorption process before reaching the large intestine. Choice A is incorrect as it has the parts in the wrong order. Choice B also has the parts in the wrong order. Choice C has the duodenum and ileum in the correct position but switches the jejunum and ileum.