Nokea
Which of the following is NOT a major endocrine organ, but produces hormones in addition to its major function?
- A. pancreas
- B. thymus
- C. kidneys
- D. pituitary
Correct Answer: C
Rationale: The correct answer is C: kidneys. The kidneys are not considered a major endocrine organ, but they do produce hormones such as erythropoietin and renin as part of their major function of regulating fluid balance and blood pressure. The pancreas (A) is a major endocrine organ producing insulin and glucagon. The thymus (B) is involved in immune function and produces hormones like thymosin. The pituitary (D) is often referred to as the master gland and secretes various hormones that regulate other endocrine glands.
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Which of the following is NOT true of growth hormone?
- A. stimulates rate of amino acid entrance into the cell
- B. stimulates protein synthesis in bones, cartilage, and muscles
- C. promotes glucose metabolism
- D. promotes fat metabolism
Correct Answer: C
Rationale: The correct answer is C: growth hormone does not promote glucose metabolism. Growth hormone primarily promotes protein synthesis in bones, cartilage, and muscles (B), stimulates the rate of amino acid entrance into the cell (A), and promotes fat metabolism (D). Glucose metabolism is mainly regulated by insulin, not growth hormone.
The adenohypophysis:
- A. secretes ADH and oxytocin.
- B. refers to the anterior pituitary gland.
- C. secretes releasing hormones.
- D. secretes glucocorticoids, mineralocorticoids, and androgens.
Correct Answer: B
Rationale: The correct answer is B because the adenohypophysis refers specifically to the anterior pituitary gland, which secretes various hormones like growth hormone, prolactin, and thyroid-stimulating hormone. Choice A is incorrect because ADH and oxytocin are actually secreted by the neurohypophysis (posterior pituitary). Choice C is incorrect because releasing hormones are secreted by the hypothalamus, not the adenohypophysis. Choice D is incorrect because glucocorticoids, mineralocorticoids, and androgens are actually secreted by the adrenal cortex, not the anterior pituitary gland.
Which is not a function of the hypothalamus?
- A. Affect heart rate
- B. Control temperature
- C. Affect water balance
- D. Secrete FSH
Correct Answer: D
Rationale: The correct answer is D: Secrete FSH. The hypothalamus produces releasing and inhibiting hormones that regulate the pituitary gland's secretion of hormones such as FSH. The hypothalamus itself does not secrete FSH. A, B, and C are functions of the hypothalamus as it is involved in regulating heart rate, temperature control, and water balance through various hormonal and neural pathways.
A patient presents with weight loss, sweating, palpitations, tachycardia, tremors, lid lag, exopthalmosis, and a goiter. Upon taking a thyroid scan, there appears to be an increased amount of iodine. What is the pathogenesis of his disease?
- A. Autoimmune Mediated
- B. Immune Complex Mediated
- C. Unknown
- D. Infection
Correct Answer: A
Rationale: The correct answer is A: Autoimmune Mediated. In this case, the patient is presenting with symptoms of hyperthyroidism along with a goiter, which is indicative of Graves' disease, an autoimmune disorder where antibodies stimulate the thyroid gland to produce excess thyroid hormones. The presence of increased iodine uptake in the thyroid scan supports this diagnosis. On the other hand, immune complex mediated diseases typically involve tissue damage caused by immune complexes, not thyroid hormone excess. The cause being unknown or infection-related are not consistent with the symptoms and thyroid scan findings in this case.
With respect to calcium metabolism / bone formation:
- A. osteoclasts secrete alkaline phosphatase
- B. osteoblasts are haemopoietic derivatives of monocyte lineage
- C. 1,25(OH)2 ???D3 and PTH stimulate both osteoblasts and osteoclasts
- D. oestrogens are thought to be protective of osteoporosis as their main effect is osteoblasts stimulation
Correct Answer: C
Rationale: Rationale for Correct Answer (C):
1,25(OH)2 D3 and PTH stimulate both osteoblasts and osteoclasts. 1,25(OH)2 D3 enhances calcium absorption in the gut, promotes bone resorption, and stimulates osteoclast activity. PTH increases calcium levels in the blood by enhancing calcium reabsorption in the kidney and stimulating osteoclast activity. Both hormones indirectly stimulate osteoblasts by increasing calcium availability for bone formation.
Summary of Incorrect Choices:
A: Osteoclasts actually secrete acid, not alkaline phosphatase.
B: Osteoblasts are derived from mesenchymal stem cells, not monocytes.
D: Estrogens have a dual effect, inhibiting bone resorption by osteoclasts and stimulating bone formation by osteoblasts; their main effect is inhibiting osteoclast activity, not solely stimulating osteoblasts.