How it Works
Try Naxlex NCLEX-RN (Free-Trial)

A patient with Cushing's disease exhibits elevated cortisol levels. Which feedback mechanism is disrupted in this condition?

A.

Negative feedback on the thyroid gland

B.

Positive feedback on the pituitary gland

C.

Negative feedback on the hypothalamus and pituitary

D.

Positive feedback on the adrenal cortex

Answer and Explanation

The Correct Answer is C

A. Negative feedback on the thyroid gland: Cushing's disease involves cortisol dysregulation and does not primarily disrupt negative feedback of the thyroid axis.
B. Positive feedback on the pituitary gland: Pituitary-driven Cushing's involves excess ACTH but the disrupted mechanism is not a physiological positive feedback loop on the pituitary.
C. Negative feedback on the hypothalamus and pituitary: Elevated cortisol should suppress CRH and ACTH via negative feedback; in Cushing's disease this feedback loop is impaired because a pituitary adenoma continues to produce ACTH despite high cortisol.
D. Positive feedback on the adrenal cortex: The adrenal cortex responds to ACTH but physiological regulation of cortisol does not operate via positive feedback on the cortex.


Get 100+ Naxlex Exit Exams for $79 Try Naxlex NCLEX-RN (14 Day Free-Trial)

Naxlex Comprehensive Predictor Exams

Free Nursing Study Resources

Related Questions

Correct Answer is D

Explanation

A. Negative feedback from insulin inhibits GH release from the anterior pituitary.:Insulin does not play a primary role in negative feedback on growth hormone release; GH regulation involves GHRH, somatostatin, and IGF-1 feedback.
B. Positive feedback from cortisol increases CRH release from the hypothalamus.:Cortisol typically exerts negative feedback on CRH (and ACTH) release, reducing hypothalamic CRH secretion rather than increasing it.
C. Positive feedback from aldosterone increases ACTH release from the anterior pituitary.:Aldosterone secretion is primarily regulated by the renin–angiotensin system and potassium levels, and aldosterone does not typically provide positive feedback to increase ACTH.
D. Negative feedback from thyroid hormones inhibits TRH release from the hypothalamus.:Thyroid hormones (T3/T4) exert negative feedback on both the hypothalamus and anterior pituitary, decreasing TRH and TSH secretion respectively.

Correct Answer is C

Explanation

A. To increase blood glucose levels directly:The hypothalamus does not directly raise blood glucose; it regulates hormones that influence this process indirectly via other glands.
B. To store and release oxytocin:Oxytocin is stored and released by the posterior pituitary, not the hypothalamus itself.
C. To secrete corticotropin-releasing hormone (CRH):The hypothalamus produces and releases CRH, which stimulates the anterior pituitary to secrete ACTH, initiating the HPA axis cascade leading to cortisol release.
D. To produce aldosterone:Aldosterone is a mineralocorticoid hormone produced by the adrenal cortex, not by the hypothalamus.

Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.

Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today

Register