Which of the following hormones are stored in the posterior pituitary gland?
- A. Prolactin
- B. Thyroid stimulating hormone (TSH)
- C. Growth hormone (GH)
- D. Adrenocorticotropic hormone (ACTH)
Correct Answer:
Rationale: Oxytocin and Vasopressin, also known as antidiuretic hormone (ADH), are the hormones stored in the posterior pituitary gland. These hormones are produced by the hypothalamus and then transported and stored in the posterior pituitary gland until they are released into the bloodstream when needed. Oxytocin plays a role in uterine contractions during childbirth and milk ejection during lactation, while Vasopressin regulates water balance in the body by acting on the kidneys to reduce urine production and conserve water. The other hormones listed, such as Prolactin, TSH, GH, ACTH, FSH, and LH, are produced by the anterior pituitary gland.
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Effect of diabetes on foetus includes all except:
- A. Microsomia
- B. Hyperbilirubinaemia
- C. Stillbirth
- D. Open neural tube defect
Correct Answer: B
Rationale: Hyperbilirubinemia is not a common effect of diabetes on the fetus. The correct effects of diabetes on the fetus include:
In a patient with centripetal obesity, acne and hirsutism. The most likely diagnosis is:
- A. Cushing's syndrome
- B. Diabetes mellitus
- C. Hypogonadism
- D. Hypothyroidism
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.
Which one of the following is acromegaly caused by?
- A. Overproduction of adrenocorticotropic hormone (ACTH)
- B. Overproduction of gonadotrophin releasing hormone (GnRH)
- C. Overproduction of growth hormone (GH)
- D. Overproduction of vasopressin (antidiuretic hormone)
Correct Answer: C
Rationale: Acromegaly is a disorder that is characterized by the overproduction of growth hormone (GH) by the pituitary gland in adults. This results in the abnormal growth of bones and tissues, leading to enlarged hands, feet, and facial features. The excess GH is usually caused by a pituitary tumor known as a somatotroph adenoma. This tumor causes the pituitary gland to produce excessive amounts of GH, which in turn leads to the symptoms associated with acromegaly. Treatment for acromegaly often involves surgical removal or reduction of the pituitary tumor, as well as medication to normalize GH levels.
Thyroid hormones (T3 and T4):
- A. increase metabolic rate.
- B. are hydrophilic as they are made from amino acids.
- C. contain iron atoms in ferrous form.
- D. stimulate the secretion of thyroid-stimulating hormone (TSH; thyrotropin).
Correct Answer: A
Rationale: Thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine), play a crucial role in regulating metabolism in the body. They are responsible for increasing the metabolic rate of cells by influencing the production of proteins and controlling how the body uses energy. This increase in metabolic rate results in processes such as increased heart rate, enhanced nutrient breakdown, and higher body temperature. Thus, option A, "increase metabolic rate," is the correct statement regarding thyroid hormones (T3 and T4).
Which of the following is the most common cause of hypothyroidism worldwide?
- A. Graves' disease
- B. Hashimoto's thyroiditis
- C. Iatrogenic hypothyroidism
- D. Iodine deficiency
Correct Answer: D
Rationale: Iodine deficiency is the most common cause of hypothyroidism worldwide. Iodine is an essential mineral required for the production of thyroid hormones. Without sufficient iodine, the thyroid gland is unable to produce an adequate amount of thyroid hormones, leading to hypothyroidism. Areas with low iodine levels in the soil or water are more prone to iodine deficiency, which can result in a range of thyroid disorders, including hypothyroidism. Efforts to prevent iodine deficiency include iodized salt programs and dietary interventions to ensure an adequate intake of iodine.