Endocrinology Exam Questions

Correct Answer: D

Rationale: Turner's syndrome is a genetic condition that affects females and is characterized by short stature and other physical abnormalities due to the absence of part or all of one of the X chromosomes. Therefore, tall stature is not characteristic of Turner's syndrome.

Correct Answer: C

Rationale: The phrase "Cushing's disease" specifically refers to the cause of Cushing's syndrome that is due to an ACTH-secreting pituitary adenoma. In this specific case, the excess production of ACTH leads to bilateral adrenal hyperplasia and oversecretion of cortisol. It is important to differentiate between Cushing's syndrome caused by a pituitary adenoma (Cushing's disease) and other causes such as adrenal adenomas, ectopic ACTH production, or iatrogenic sources.

Correct Answer: A

Rationale: Centripetal obesity, acne, and hirsutism are classic features of Cushing's syndrome. Cushing's syndrome results from prolonged exposure to high levels of cortisol, which can be due to various causes such as adrenal tumors, pituitary adenomas, or exogenous glucocorticoid use. Centripetal obesity refers to the characteristic fat distribution pattern seen in Cushing's syndrome, where fat accumulates mainly in the face, neck, and trunk while sparing the limbs. Acne and hirsutism are also commonly seen in Cushing's syndrome due to the hormonal imbalances caused by excess cortisol. Testing for serum cortisol levels, dexamethasone suppression tests, and imaging studies can help confirm the diagnosis of Cushing's syndrome in a patient presenting with these symptoms.

Correct Answer: A

Rationale: The receptors for non-steroid peptide hormones are typically found on the plasma membrane of target cells. These hormones are large or polar molecules that cannot easily diffuse through the cell membrane. Instead, they bind to specific receptors on the cell surface, initiating signaling pathways that eventually lead to changes within the cell. Once the peptide hormone binds to its receptor on the plasma membrane, secondary messenger systems are activated to relay the signal into the cell and initiate the appropriate cellular response. This distinct mechanism of action highlights the importance of the plasma membrane as the location of receptors for non-steroid peptide hormones.

Correct Answer: B

Rationale: Myxoedema coma is a severe form of hypothyroidism that can lead to the slowing down of various body functions, including reduced heart rate (bradycardia). As the condition progresses and the body's metabolism becomes more depressed, one of the compensatory mechanisms is an increase in heart rate (tachycardia) to try to maintain adequate tissue perfusion. Therefore, tachycardia is a characteristic feature of myxoedema coma, rather than hypertension or euthermia which are not typically associated with this condition. Hypoventilation is also a common feature of myxoedema coma due to the decreased metabolic rate and respiratory drive.