Endocrinology Practice Questions -Nurselytic

Correct Answer: A

Rationale:
Step-by-step rationale for why answer A is correct:
1. Oxytocin is synthesized in the hypothalamus and released into the bloodstream.
2. In the plasma, oxytocin binds to neurophysin, a carrier protein.
3. This binding helps stabilize oxytocin and regulate its release and distribution.
4.
Therefore, choice A is correct as oxytocin is bound to neurophysin in plasma.

Summary:
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Choice B is incorrect as oxytocin stimulates milk ejection, not inhibits milk production.
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Choice C is incorrect as oxytocin promotes myometrial contraction during labor.
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Choice D is incorrect as oxytocin can enhance sperm motility, not inhibit it.

Correct Answer: D

Rationale:
Step-by-step rationale:
1. Gynaecomastia is a known side effect of spironolactone, digitalis, and cimetidine.
2. Rifampicin is not associated with gynaecomastia.
3. Rifampicin is an antibiotic used to treat tuberculosis and other infections.
4. The mechanism of action of rifampicin does not involve hormonal changes that could lead to gynaecomastia.

Summary of incorrect choices:
- A: Spironolactone is a potassium-sparing diuretic that can cause gynaecomastia.
- B: Digitalis (digoxin) can lead to gynaecomastia as a side effect.
- C: Cimetidine, an H2 receptor antagonist, is also known to cause gynaecomastia.

Correct Answer: B

Rationale: The correct answer is B: Kidney disease. Oral contraceptive pills are contraindicated in patients with kidney disease due to the risk of impaired drug clearance and potential adverse effects on renal function. Breast cancer (
A), liver disease (
C), and prior history of deep venous thrombosis (
D) are all contraindications to the use of oral contraceptives due to increased risks of complications such as thrombosis or exacerbation of underlying conditions.

Correct Answer: B

Rationale: Thyroid acropathy, also known as thyroid dermopathy, is a skin condition commonly associated with Graves' disease. This autoimmune disorder causes an overactive thyroid gland, leading to high levels of thyroid hormones in the blood. The excess thyroid hormones can trigger changes in the skin, resulting in thyroid acropathy. Subclinical hypothyroidism (choice
A) is characterized by slightly elevated TSH levels with normal thyroid hormone levels, not typically associated with thyroid acropathy. Myxoedema (choice
C) refers to severe hypothyroidism and is not linked to thyroid acropathy. Medullary carcinoma of the thyroid (choice
D) is a type of thyroid cancer and is not known to cause thyroid acropathy.
Therefore, the correct answer is B, Graves' disease, as it is the most common condition associated with thyroid acropathy.

Correct Answer: C

Rationale: Leydig cells are found in the testes and are responsible for producing testosterone, a crucial male sex hormone. This hormone is essential for the development of male reproductive organs, secondary sexual characteristics, and sperm production. Oestrogen is primarily produced by the ovaries in females. Androgen binding globulin is a protein that binds to testosterone in the bloodstream but is not produced by Leydig cells. Semen is produced by the accessory glands in the male reproductive system, not by Leydig cells.
Therefore, the correct answer is C: Testosterone.