Hormone feedback regulation Knowledge-Based Practice

Questions

1. 1.

   Which endocrine response occurs through negative feedback when circulating cortisol concentrations rise above the homeostatic set point?

   • A) The anterior pituitary increases the secretion of adrenocorticotropic hormone (ACTH).
   • B) The adrenal medulla increases the secretion of epinephrine.
   • C) The hypothalamus increases the secretion of corticotropin-releasing hormone (CRH).
   • D) The anterior pituitary and hypothalamus decrease the secretion of ACTH and CRH, respectively.
2. 2.

   When blood calcium ion concentration drops below normal physiological levels, which hormonal response is initiated to restore calcium homeostasis through negative feedback?

   • A) The thyroid gland increases calcitonin secretion to stimulate bone deposition.
   • B) The adrenal cortex secretes aldosterone to prevent renal calcium excretion.
   • C) The anterior pituitary releases growth hormone to activate calcium synthesis in osteoblasts.
   • D) The parathyroid glands increase parathyroid hormone (PTH) secretion to promote calcium reabsorption and bone resorption.
3. 3.

   Which of the following physiological processes is regulated by a positive hormonal feedback loop rather than a negative feedback mechanism?

   • A) Suppression of antidiuretic hormone (ADH) release when blood osmolarity decreases
   • B) Secretion of parathyroid hormone (PTH) in response to declining blood calcium concentrations
   • C) Inhibition of adrenocorticotropic hormone (ACTH) secretion by elevated blood cortisol levels
   • D) Stimulation of oxytocin release induced by pressure on the cervix during childbirth
4. 4.

   Which physiological response occurs as a negative feedback mechanism when blood glucose concentration falls below the homeostatic set point?

   • A) Alpha cells of the pancreas secrete glucagon, promoting glycogen breakdown in the liver to elevate circulating glucose levels.
   • B) Beta cells of the pancreas secrete insulin, stimulating widespread cellular glucose uptake to lower circulating glucose levels.
   • C) The anterior pituitary gland releases adrenocorticotropic hormone, prompting muscle tissue to absorb glucose and synthesize glycogen.
   • D) The adrenal cortex releases aldosterone, which directly prevents the renal excretion of glucose into the collecting ducts.
5. 5.

   In the human endocrine system, how does an elevated blood concentration of thyroxine ($T_4$) restore homeostatic balance through negative feedback regulation?

   • A) It stimulates the anterior pituitary to produce greater amounts of thyroid-stimulating hormone (TSH).
   • B) It triggers the parathyroid glands to increase the secretion of parathyroid hormone (PTH).
   • C) It prompts the hypothalamus to synthesize and release more thyrotropin-releasing hormone (TRH).
   • D) It inhibits the secretion of thyrotropin-releasing hormone (TRH) by the hypothalamus and thyroid-stimulating hormone (TSH) by the anterior pituitary.

Answers and step-by-step solutions appear after you finish the test.