Endocrinology & Reproduction

Topics in this chapter

• Hormone Action and Feedback
• Hypothalamic-Pituitary Regulation
• ADH and Renal Water Balance
• Thyroid and Calcium Homeostasis
• Adrenal Cortex and Cushing Syndrome
• Insulin and Metabolic Regulation
• Male Reproduction and Spermatogenesis
• Female Reproduction and Menstrual Cycle

Practice questions

1. Question 1Q-427632

   A 34-year-old female presents to the endocrinology clinic with complaints of spontaneous milk secretion from both breasts and irregular menses over the past six months. Laboratory evaluation reveals a serum prolactin level of 120 ng/mL. Which of the following hypothalamic factors exerts the primary tonic inhibitory control over the secretion of this hormone?

   1. A.Somatostatin
   2. B.Dopamine
   3. C.Thyrotropin-releasing hormone
   4. D.Gonadotropin-releasing hormone
   See the answer and solution
2. Question 2Q-C32315

   A 45-year-old man undergoes a total thyroidectomy for papillary thyroid carcinoma. Four days post-operatively, he complains of perioral numbness, tingling in his fingers, and muscle cramps. On physical examination, tapping the facial nerve anterior to the external auditory meatus results in ipsilateral twitching of the facial muscles. Which of the following intracellular signaling events is primarily responsible for this patient's acute neuromuscular hyperexcitability?

   1. A.Decreased threshold for sodium channel activation due to reduction in extracellular ionized calcium
   2. B.Increased intracellular potassium concentration causing continuous membrane depolarization
   3. C.Blockage of postsynaptic neuromuscular nicotinic acetylcholine receptors
   4. D.Excessive release of parathyroid hormone from remnant tissue
   See the answer and solution
3. Question 3Q-DEE476

   During the mid-menstrual cycle surge of gonadotropins, which of the following paradoxical feedback effects does estrogen exert on the anterior pituitary and hypothalamus?

   1. A.Negative feedback inhibition of both FSH and LH
   2. B.Positive feedback stimulation of both FSH and LH secretion
   3. C.Inhibition of GnRH pulse frequency while stimulating GnRH amplitude
   4. D.Direct suppression of pituitary gonadotroph responsiveness
   See the answer and solution
4. Question 4Q-DFCA13

   A 28-year-old pregnant woman in her 38th week of gestation is monitored during labor. The stretching of the uterine cervix by the fetal presenting part stimulates oxytocin release from the posterior pituitary, which in turn increases uterine contractions and further stretches the cervix. This physiological mechanism is a classic example of:

   1. A.Negative feedback control
   2. B.Positive feedback control
   3. C.Feedforward regulation
   4. D.Autocrine signaling
   See the answer and solution
5. Question 5Q-1F7C00

   A researcher is studying the intracellular mechanisms of various peptide and steroid hormones in an endocrine lab. Which of the following hormones utilizes a receptor that inherently possesses intrinsic tyrosine kinase activity upon ligand binding?

   1. A.Thyroid-stimulating hormone (TSH)
   2. B.Insulin
   3. C.Adrenocorticotropic hormone (ACTH)
   4. D.Antidiuretic hormone (ADH)
   See the answer and solution