Endocrinology Exam Questions

Correct Answer: A

Rationale: Myxoedema is a term used to describe severe hypothyroidism. The characteristic features of myxoedema include sinus bradycardia (choice B), solid oedema (choice C), and madarosis (choice D), which refers to loss of eyebrows and eyelashes. However, a butterfly rash is not a typical feature of myxoedema. A butterfly rash is commonly associated with conditions like systemic lupus erythematosus rather than myxoedema.

Correct Answer: B

Rationale: Nephrogenic diabetes insipidus (NDI) is a condition where the kidneys are unable to respond to antidiuretic hormone (ADH) as they should, leading to excessive urination and extreme thirst. One of the main causes of nephrogenic diabetes insipidus is the use of certain medications, with lithium being the most common culprit. Lithium can interfere with the kidney's response to ADH, resulting in decreased water reabsorption and the characteristic symptoms of diabetes insipidus. Other causes of NDI can include genetic mutations affecting the vasopressin receptor gene or other underlying conditions such as hypercalcemia, hypokalemia, or obstructive uropathy.

Correct Answer: C

Rationale: Autonomic neuropathy in diabetes can manifest with various symptoms, such as retrograde ejaculation (A), gustatory sweating (B), and hypoglycemic unresponsiveness (D). Mononeuritis multiplex (C) is not typically associated with autonomic neuropathy in diabetes. Mononeuritis multiplex is a condition characterized by damage to at least two separate nerve areas resulting in weakness, pain, and sensory loss. Autonomic neuropathy in diabetes tends to affect the autonomic nerves that control involuntary bodily functions, leading to symptoms such as gastrointestinal issues, cardiovascular abnormalities, and sexual dysfunction, but mononeuritis multiplex is not a common feature of this condition.

Correct Answer: C

Rationale: Hormones are chemical messengers that are produced by various glands in the body and released into the bloodstream to signal and regulate the activity of specific target cells. Unlike energy sources that can be metabolized for energy production (like carbohydrates and fats), hormones are not typically used as an energy source themselves (Choice B). Hormones are typically not biologically inert by themselves (Choice A), as they have specific functions in regulating various physiological processes in the body. While some hormones may be stored in secretory granules before release, not all hormones are stored in this manner (Choice D). Additionally, hormones are not always released by exocytosis (Choice E), as some hormones can also be released through other mechanisms such as diffusion. The correct choice, therefore, is C: hormones are incorporated as a structural moiety into another molecule, as they bind to specific receptors on target cells to elicit a cellular response and regulate physiological functions.

Correct Answer: B

Rationale: Karyotype 47, XYY refers to the presence of an extra Y chromosome in males. This condition is known as XYY syndrome, also called Jacob's syndrome. Individuals with XYY syndrome are typically phenotypically male but may have some associated physical and behavioral characteristics. These individuals are often referred to as "supermales" due to the presence of the extra Y chromosome. This is different from true hermaphroditism, Klinefelter's syndrome, and gonadal dysgenesis, which have distinct chromosomal patterns and manifestations.