Hypocalcemic tetany:
- A. causes a flaccid paralysis.
- B. resembles neuromuscular blockade by curare.
- C. may be caused by a deficiency of PTH.
- D. is caused by a deficiency of insulin.
Correct Answer: C
Rationale: Step-by-step rationale:
1. Hypocalcemic tetany is associated with low levels of calcium in the blood.
2. Parathyroid hormone (PTH) plays a crucial role in calcium regulation.
3. A deficiency of PTH can lead to decreased calcium levels, causing tetany.
4. Therefore, choice C is correct as hypocalcemic tetany may be caused by a deficiency of PTH.
Summary:
A: Incorrect. Hypocalcemic tetany leads to muscle spasms, not flaccid paralysis.
B: Incorrect. Curare blockade affects neuromuscular transmission, not calcium levels.
D: Incorrect. Insulin deficiency is associated with hyperglycemia, not hypocalcemia leading to tetany.
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Carbohydrate absorption:
- A. all glucose, galactose and fructose is co-transported with Na by the SGLT-2 transporter into enterocytes
- B. all glucose/galactose and fructose is transported across the basolateral membrane by GLUT2
- C. fructose absorption is a secondary active transport mechanism
- D. absorption is decreased by insulin
Correct Answer: B
Rationale: The correct answer is B because glucose, galactose, and fructose are transported across the basolateral membrane by the GLUT2 transporter. This occurs after they are absorbed into enterocytes through various transport mechanisms. Choice A is incorrect because SGLT-2 transporter is responsible for glucose and galactose absorption, not fructose. Choice C is incorrect as fructose is absorbed through facilitated diffusion, not secondary active transport. Choice D is incorrect because insulin actually increases carbohydrate absorption by upregulating GLUT2 expression.
Complete the following sentence: Hormones are chemical messengers that…
- A. Remain at a constant concentration in the blood
- B. Are synthesised by plasma proteins
- C. Are only produced after puberty
- D. Alter the activity of target tissues
Correct Answer: D
Rationale: The correct answer is D because hormones alter the activity of target tissues to regulate various physiological processes in the body. Hormones act on specific receptors in target tissues to initiate a response. Option A is incorrect because hormone levels fluctuate to maintain homeostasis. Option B is incorrect because hormones are typically synthesized by endocrine glands, not plasma proteins. Option C is incorrect because hormones are produced throughout life, not just after puberty.
Which of these hormones is made by the posterior pituitary?
- A. FSH
- B. LH
- C. ACTH
- D. ADH
Correct Answer: D
Rationale: The correct answer is D: ADH (Antidiuretic Hormone). ADH is produced by the posterior pituitary gland and regulates water balance in the body by acting on the kidneys to reduce urine output. FSH, LH, and ACTH are produced by the anterior pituitary gland and have different functions related to reproductive health and stress response. The key to this question is knowing the specific hormones produced by the posterior pituitary gland, making D the correct choice.
Which of the following is most responsive to treatment with thyroxine?
- A. Diabetes mellitus
- B. Hyperglycemia
- C. Myxedema
- D. Graves’ disease
Correct Answer: C
Rationale: Rationale:
1. Myxedema is caused by hypothyroidism, which can be effectively treated with thyroxine.
2. Thyroxine is a synthetic form of thyroid hormone that helps restore thyroid hormone levels.
3. Myxedema symptoms such as fatigue, weight gain, and cold intolerance improve with thyroxine treatment.
Summary of Incorrect Choices:
A. Diabetes mellitus and hyperglycemia are not directly related to thyroid hormone levels.
B. Hyperglycemia is not primarily treated with thyroxine.
D. Graves' disease is a thyroid disorder characterized by hyperthyroidism, which requires different treatments than hypothyroidism.
What is the most critical need for the child with newly diagnosed cretinism?
- A. Thyroidectomy
- B. Administration of a radioactive cocktail of 131I (radioactive iodine)
- C. Replacement dose of thyroid hormones
- D. Replacement dose of calcitonin
Correct Answer: C
Rationale: The correct answer is C: Replacement dose of thyroid hormones. In newly diagnosed cretinism, there is a deficiency of thyroid hormones, leading to developmental delays and other health issues. Administering replacement thyroid hormones is crucial to normalize hormone levels and support proper growth and development. Thyroidectomy (choice A) is not necessary in this case as the goal is to supplement the missing hormones. Option B, the administration of radioactive iodine cocktail, is used to treat hyperthyroidism, not hypothyroidism. Choice D, replacement dose of calcitonin, is not relevant as calcitonin is involved in calcium regulation, not thyroid hormone production. Thus, the most critical need for the child with newly diagnosed cretinism is the replacement dose of thyroid hormones to address the underlying hormonal deficiency.