Nokea
The receptors for non-steroid peptide hormones are found on the ______.
- A. plasma membrane
- B. nuclear envelope
- C. mitochondria
- D. lysosomes
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.
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Commonest enzymatic defect for development of congenital adrenal hyperplasia is:
- A. C-21 hydroxylase deficiency
- B. 3b dehydrogenase deficiency
- C. C-11 hydroxylase deficiency
- D. C-17 hydroxylase deficiency
Correct Answer: A
Rationale: C-21 hydroxylase deficiency is the most common enzymatic defect leading to the development of congenital adrenal hyperplasia (CAH). This enzyme is necessary for the synthesis of cortisol and aldosterone in the adrenal glands. When there is a deficiency in C-21 hydroxylase, the pathway is shifted towards the production of androgens instead of cortisol and aldosterone, leading to excess androgen production. This results in the characteristic features of CAH, such as ambiguous genitalia in females and virilization in both males and females. Other enzyme deficiencies listed in the choices can also lead to different types of CAH but are less common compared to C-21 hydroxylase deficiency.
"Pseudo-Cushing's syndrome' may be found in all except:
- A. Myxoedema
- B. Chronic alcoholism
- C. Obesity
- D. Depression
Correct Answer: A
Rationale: Pseudo-Cushing's syndrome is a condition that mimics the symptoms of Cushing's syndrome but is not actually caused by excess cortisol production by the adrenal glands. It can be caused by various conditions such as chronic alcoholism, obesity, depression, and certain medications. However, myxoedema (also known as severe hypothyroidism) is not typically associated with pseudo-Cushing's syndrome. Myxoedema is characterized by low thyroid hormone levels, which would not lead to the symptoms of pseudo-Cushing's syndrome.
Enlargement of the bones of the hands, feet, and face due to overproduction of growth hormone is called :
- A. Acromegaly
- B. Cushing syndrome
- C. Gigantism
- D. Myxedema
Correct Answer: A
Rationale: Acromegaly is the condition characterized by the enlargement of the bones of the hands, feet, and face due to the overproduction of growth hormone in adults. This excess growth hormone typically comes from a benign tumor in the pituitary gland, leading to the gradual enlargement of these body parts. Cushing syndrome, on the other hand, is caused by prolonged exposure to high levels of cortisol and is not directly related to bone enlargement. Gigantism is the condition of excessive growth in height due to overproduction of growth hormone occurring in children before the closure of growth plates. Myxedema is a term used to describe severe hypothyroidism and is not directly associated with bone enlargement.
Which of the following is not a feature of autonomic neuropathy in diabetes?
- A. Retrograde ejaculation
- B. Gustatory sweating
- C. Mononeuritis multiplex
- D. Hypoglycemic unresponsiveness
Correct Answer: C
Rationale: Autonomic neuropathy in diabetes can manifest with various symptoms, such as retrograde ejaculation (A), gustatory sweating (B), and hypoglycemic unresponsiveness (D). Mononeuritis multiplex (C) is not typically associated with autonomic neuropathy in diabetes. Mononeuritis multiplex is a condition characterized by damage to at least two separate nerve areas resulting in weakness, pain, and sensory loss. Autonomic neuropathy in diabetes tends to affect the autonomic nerves that control involuntary bodily functions, leading to symptoms such as gastrointestinal issues, cardiovascular abnormalities, and sexual dysfunction, but mononeuritis multiplex is not a common feature of this condition.
Which of the following statements best describes Hashimoto's thyroiditis?
- A. Inflammation of the thyroid gland as the result of a virus. The disease is often preceded by an upper respiratory tract infection.
- B. A destructive autoimmune disease caused by auto-reactive antibodies against thyroglobulin.
- C. Iodine deficiency
- D. thyroid gland
Correct Answer: B
Rationale: Hashimoto's thyroiditis is an autoimmune disease where the immune system mistakenly attacks the thyroid gland. The antibodies produced by the immune system target the thyroglobulin in the thyroid gland, leading to its destruction over time. This results in decreased thyroid hormone production, leading to hypothyroidism. Therefore, choice B, "A destructive autoimmune disease caused by auto-reactive antibodies against thyroglobulin," best describes Hashimoto's thyroiditis.