Nokea
All of the following represent examples of hypothalamic-pituitary negative feedback except:
- A. Cortisol on the CRH-ACTH axis
- B. Gonadal steroids on the GnRH-LH/FSH axis
- C. IGF-1 on the growth hormone-releasing hormone (GHRH)-GH axis
- D. Renin-angiotensin-aldosterone axis
Correct Answer: D
Rationale: The renin-angiotensin-aldosterone axis does not involve the hypothalamus or pituitary gland; instead, it primarily involves the kidneys and the renin-secreting cells. In this axis, renin is released in response to low blood pressure, leading to the formation of angiotensin II and the subsequent release of aldosterone from the adrenal glands. Feedback mechanisms for this axis primarily involve the regulation of renin release based on blood pressure rather than involving direct negative feedback from downstream hormones on the hypothalamus or pituitary gland. On the other hand, choices A, B, and C all involve classic examples of hypothalamic-pituitary negative feedback loops where the end hormone suppresses the release of the stimulating hormones at the hypothalamic and pituitary levels.
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Calcification of basal ganglia is seen in:
- A. Primary hyperparathyroidism
- B. Hypoparathyroidism
- C. Secondary hyperparathyroidism
- D. Milk-alkali syndrome
Correct Answer: A
Rationale: Primary hyperparathyroidism is a condition characterized by the overproduction of parathyroid hormone (PTH) by the parathyroid glands, leading to elevated levels of calcium in the blood. This excessive calcium can cause calcification in various tissues, including the basal ganglia of the brain. The calcification of the basal ganglia in primary hyperparathyroidism is a well-known radiological finding and can be visualized on imaging studies such as CT scans or MRI. Hypoparathyroidism, on the other hand, is characterized by low levels of PTH and results in decreased serum calcium levels, making it an unlikely cause of basal ganglia calcification. Secondary hyperparathyroidism is associated with chronic kidney disease and is also characterized by high PTH levels, but basal ganglia calcification is not a typical manifestation of this condition. Milk-alkali syndrome is a disorder characterized by excessive intake of
Which test is used to evaluate blood glucose levels over the previous 2 months?
- A. Methemoglobin
- B. Hemoglobin A1c
- C. Fasting blood sugar
- D. C peptide protein
Correct Answer: B
Rationale: Hemoglobin A1c, also known as HbA1c or glycated hemoglobin, is a blood test that measures the average blood glucose level over the previous 2 to 3 months. This test is useful in monitoring long-term blood glucose control in individuals with diabetes. Hemoglobin A1c provides an indication of how well blood glucose levels have been controlled over time, reflecting the average blood sugar levels during the lifespan of red blood cells, which is typically around 2 to 3 months. A higher Hemoglobin A1c level indicates poorer blood glucose control and an increased risk of diabetes complications.
Increased gonadal production of oestrogen is seen in:
- A. Third trimester of pregnancy
- B. Congenital adrenal hyperplasia
- C. Polycystic ovarian disease
- D. Testicular feminization syndrome
Correct Answer: C
Rationale: Polycystic ovarian disease, also known as polycystic ovary syndrome (PCOS), is a common endocrine disorder characterized by increased levels of androgens (male hormones) and disrupted estrogen production in the ovaries. The hormonal imbalance seen in PCOS leads to increased gonadal production of estrogen. This condition is often associated with symptoms such as irregular menstrual cycles, infertility, acne, and excess facial or body hair growth. In contrast, the other options do not typically involve increased gonadal production of estrogen as seen in PCOS.
A person with acromegaly usually has:
- A. prognathism and large fleshy lips.
- B. hypoglycemia.
- C. a growth hormone deficiency.
- D. protruding eye balls.
Correct Answer: A
Rationale: Acromegaly is a hormonal disorder that results from the overproduction of growth hormone (GH) in adulthood. One of the key physical characteristics associated with acromegaly is the enlargement of facial features. People with acromegaly often develop prognathism, which is a condition where the lower jaw protrudes forward, leading to a prominent lower face. Additionally, they may have large fleshy lips due to the soft tissue swelling that occurs as a result of excess GH. Other common signs of acromegaly include enlarged hands and feet, thickened skin, and joint pain.
Thyrotoxicosis may be featured by all except:
- A. Myopathy
- B. Pretibial myxoedema
- C. Hypernatraemia
- D. Atrial fibrillation
Correct Answer: A
Rationale: Thyrotoxicosis, also known as hyperthyroidism, is a condition characterized by excessive thyroid hormone production by the thyroid gland. Symptoms of thyrotoxicosis can include weight loss, heat intolerance, tremors, hyperactivity, and fatigue. While musculoskeletal symptoms such as weakness and tremors are common in thyrotoxicosis, true myopathy (muscle disease) is not a typical feature of the condition. Therefore, myopathy is the correct choice among the given options.