Nokea
Thyroid-stimulating hormone (TSH):
- A. is a glycoprotein hormone.
- B. is synthesized in the follicular cells of the thyroid gland.
- C. has gonadotropic activity.
- D. stimulates the activity of parafollicular thyroid cells.
Correct Answer: A
Rationale: Thyroid-stimulating hormone (TSH) is a glycoprotein hormone that is produced and secreted by the anterior pituitary gland. It acts on the thyroid gland to stimulate the production and release of thyroid hormones, T3 (triiodothyronine) and T4 (thyroxine). TSH plays a crucial role in regulating the function of the thyroid gland and maintaining overall thyroid hormone levels in the body.
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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.
Regarding syndrome of inappropriate antidiuretic hormone (SIADH), which is true?
- A. Hyponatremia is dilutional
- B. Urine is relatively hypertonic to plasma
- C. ADH-mediated water reabsorption does not occur
- D. Renal function is jeopardized
Correct Answer: A
Rationale: In the syndrome of inappropriate antidiuretic hormone (SIADH), there is excessive secretion of antidiuretic hormone (ADH) leading to increased water reabsorption in the kidney tubules. This results in dilutional hyponatremia because the amount of water reabsorbed is greater than the electrolytes, such as sodium, leading to a relative decrease in their concentration in the blood. As a result, hyponatremia occurs in SIADH, contributing to symptoms such as nausea, confusion, and seizures due to the imbalance in electrolytes.
Which one of the following is acromegaly caused by?
- A. Overproduction of adrenocorticotropic hormone (ACTH)
- B. Overproduction of gonadotrophin releasing hormone (GnRH)
- C. Overproduction of growth hormone (GH)
- D. Overproduction of vasopressin (antidiuretic hormone)
Correct Answer: C
Rationale: Acromegaly is a disorder that is characterized by the overproduction of growth hormone (GH) by the pituitary gland in adults. This results in the abnormal growth of bones and tissues, leading to enlarged hands, feet, and facial features. The excess GH is usually caused by a pituitary tumor known as a somatotroph adenoma. This tumor causes the pituitary gland to produce excessive amounts of GH, which in turn leads to the symptoms associated with acromegaly. Treatment for acromegaly often involves surgical removal or reduction of the pituitary tumor, as well as medication to normalize GH levels.
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.
Charcot joint in diabetes mellitus commonly affects:
- A. Hip
- B. Shoulder
- C. Knee
- D. Foot
Correct Answer: D
Rationale: Charcot joint, also known as neuropathic arthropathy, is a serious complication of diabetes mellitus that affects the joints. It commonly affects the foot, especially the midfoot and hindfoot. The condition is characterized by joint deformities, fractures, and dislocations due to nerve damage and loss of sensation in the foot. The repetitive stress on the foot from walking or weight-bearing activities can lead to progressive joint destruction and deformity. It is important for individuals with diabetes to monitor their foot health closely and seek prompt medical attention if they notice any changes or deformities in their feet.