Nokea
Earliest changes observed by ophthalmoscope in background retinopathy of diabetes is:
- A. Venous dilatation
- B. Microaneurysms
- C. Increased capillary permeability
- D. Arteriovenous shunts
Correct Answer: B
Rationale: The earliest changes observed by ophthalmoscope in background retinopathy of diabetes is typically the presence of microaneurysms. These are small dilations of retinal capillaries due to weakening of the vessel walls caused by diabetes-induced damage. Microaneurysms are a hallmark sign of diabetic retinopathy and are often the first visible sign on retinal examination. Other changes in diabetic retinopathy, such as venous dilatation, increased capillary permeability, and arteriovenous shunts, may develop later in the disease process as it progresses.
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The triad of hyponatraemia, haemodilution and urine hypertonic to plasma suggest diagnosis of:
- A. Nephrotic syndrome
- B. SIADH
- C. Nephrogenic diabetes insipidus
- D. Addison's disease
Correct Answer: B
Rationale: The triad of hyponatremia (low sodium levels in the blood), haemodilution (increased plasma volume), and urine hypertonic to plasma (high urine osmolality compared to blood osmolality) is characteristic of Syndrome of Inappropriate Antidiuretic Hormone (SIADH). In SIADH, there is excessive release of antidiuretic hormone (ADH), also known as vasopressin, leading to water retention by the kidneys and dilutional hyponatremia. This condition results in the body holding onto water, causing hyponatremia and dilution of the blood. The urine being hypertonic compared to plasma indicates that the kidneys are reabsorbing water effectively and concentrating the urine.
All of the following represent examples of hypothalamic-pituitary negative feedback except:
- A. Cortisol on the CRH-ACTH axis
- B. Gonadal steroids on the GnRH-LH/FSH axis
- C. IGF-1 on the growth hormone-releasing hormone (GHRH)-GH axis
- D. Renin-angiotensin-aldosterone axis
Correct Answer: D
Rationale: The renin-angiotensin-aldosterone axis does not involve the hypothalamus or pituitary gland; instead, it primarily involves the kidneys and the renin-secreting cells. In this axis, renin is released in response to low blood pressure, leading to the formation of angiotensin II and the subsequent release of aldosterone from the adrenal glands. Feedback mechanisms for this axis primarily involve the regulation of renin release based on blood pressure rather than involving direct negative feedback from downstream hormones on the hypothalamus or pituitary gland. On the other hand, choices A, B, and C all involve classic examples of hypothalamic-pituitary negative feedback loops where the end hormone suppresses the release of the stimulating hormones at the hypothalamic and pituitary levels.
Which of the following is a complication of diabetes mellitus?
- A. Gastroparesis
- B. Exophthalmos
- C. Hirsutism
- D. Moon facies
Correct Answer: A
Rationale: Gastroparesis is a complication of diabetes mellitus. It is a condition that affects the normal spontaneous movement of the muscles in the stomach, causing delayed emptying of food from the stomach into the small intestine. This can lead to symptoms such as nausea, vomiting, bloating, and poor appetite. Diabetes can damage the nerves that control the stomach muscles, resulting in gastroparesis. Managing blood sugar levels and following a proper diet can help in controlling the symptoms of gastroparesis in individuals with diabetes. Exophthalmos, hirsutism, and moon facies are not typically associated with complications of diabetes mellitus.
Oxytocin:
- A. is not produced in males.
- B. inhibits lactation.
- C. stimulates smooth muscle contraction.
- D. is produced primarily in the SON in the hypothalamus.
Correct Answer: C
Rationale: Oxytocin is a hormone that is produced in both males and females. In females, oxytocin plays a crucial role in various physiological processes, notably during labor and childbirth. Oxytocin acts on the smooth muscles of the uterus, causing them to contract during labor (parturition) and helps in the ejection of milk during breastfeeding. This hormone is primarily synthesized in the paraventricular nucleus (PVN) and the supraoptic nucleus (SON) of the hypothalamus and stored in the posterior pituitary gland before being released into the bloodstream. Overall, oxytocin's main function is to stimulate smooth muscle contraction in the uterus and the mammary glands.
Which cranial nerve is not involved in acromegaly?
- A. VIII
- B. III, IV, VI
- C. V
- D. Il
Correct Answer: A
Rationale: Acromegaly is a disorder caused by the overproduction of growth hormone in adulthood, usually due to a pituitary tumor. The cranial nerves that may be affected in acromegaly are Cranial Nerves III, IV, VI (oculomotor, trochlear, abducens) due to compression of the optic chiasm by the expanding tumor. Cranial Nerve V (trigeminal nerve) may also be affected given its close proximity to the pituitary gland. However, Cranial Nerve VIII (vestibulocochlear nerve) is not typically involved in acromegaly.