ATI RN
Endocrine System MCQ Questions Questions
Question 1 of 5
Mole for mole, which of the following has the greatest effect on Na+ excretion?
Correct Answer: D
Rationale: The correct answer is D: Aldosterone. Aldosterone directly influences the reabsorption of sodium in the kidney tubules, leading to increased Na+ excretion. Progesterone (A) does not have a significant effect on Na+ excretion. Cortisol (B) mainly affects glucose metabolism and has minimal impact on Na+ excretion. Vasopressin (C) primarily regulates water reabsorption, not Na+ excretion. Therefore, Aldosterone has the greatest effect on Na+ excretion due to its specific role in sodium reabsorption in the kidneys.
Question 2 of 5
Most of the endocrine system is regulated by:
Correct Answer: A
Rationale: The correct answer is A: negative feedback mechanisms. Negative feedback mechanisms are essential in regulating hormone levels within a narrow range to maintain homeostasis. When hormone levels rise, negative feedback mechanisms signal the body to decrease production, and vice versa. Positive feedback mechanisms amplify hormone production, not regulate it. Hormone-receptor complexes and hormone-gene complexes are important for hormone actions but do not regulate the overall endocrine system.
Question 3 of 5
The posterior pituitary gland stores and secretes
Correct Answer: A
Rationale: Step-by-step rationale: 1. The posterior pituitary gland stores oxytocin and antidiuretic hormone (ADH). 2. Oxytocin is responsible for uterine contractions and milk ejection. 3. ADH regulates water balance by controlling urine concentration. 4. These hormones are produced in the hypothalamus and released from the posterior pituitary. 5. Choice A is correct as it accurately identifies the hormones stored and secreted by the posterior pituitary. Summary: - Choice B is incorrect because human growth hormone and thyroid stimulating hormone are not stored or secreted by the posterior pituitary. - Choice C is incorrect because prolactin and follicle stimulating hormone are produced by the anterior pituitary. - Choice D is incorrect because glucocorticoids and androgens are not stored or secreted by the posterior pituitary.
Question 4 of 5
Chemical substances secreted by cells into the extracellular fluids that regulate the metabolic function of other cells in the body are called ________.
Correct Answer: D
Rationale: The correct answer is D: hormones. Hormones are chemical substances secreted by cells into extracellular fluids to regulate metabolic functions in other cells. They act as messengers, traveling through the bloodstream to target tissues. Enzymes (A) are catalysts that accelerate chemical reactions. Antibodies (B) are proteins produced by the immune system to neutralize pathogens. Proteins (C) are essential macromolecules for various cellular functions but do not specifically regulate metabolic functions in other cells like hormones do.
Question 5 of 5
Steroid hormones exert their action by ________.
Correct Answer: A
Rationale: The correct answer is A because steroid hormones are lipid-soluble molecules that can pass through the cell membrane and bind to intracellular receptors in the nucleus. This binding activates or inhibits gene transcription, leading to changes in protein synthesis and cellular responses. Choice B is incorrect because cAMP activity is typically associated with peptide hormones, not steroid hormones. Choice C is incorrect because steroid hormones do not stimulate glycogen synthesis. Choice D is incorrect because steroid hormones do not directly affect blood pressure regulation.