Nokea
Which of the following are not causes of neurogenic diabetes insipidus?
- A. Sheehan's syndrome
- B. Mutations in the vasopressin (ADH) receptor gene
- C. Meningitis
- D. Mutations in the vasopressin gene
Correct Answer: D
Rationale: Neurogenic diabetes insipidus is due to a deficiency in vasopressin (antidiuretic hormone, ADH) production in the hypothalamus or a failure of proper vasopressin release from the posterior pituitary. Causes of neurogenic DI typically involve factors affecting vasopressin synthesis, storage, or release. However, mutations in the vasopressin gene itself would be a cause of genetic forms of diabetes insipidus, not neurogenic diabetes insipidus. Common causes of neurogenic diabetes insipidus include traumatic brain injury, brain tumors, pituitary adenomas, meningitis, and Sheehan's syndrome.
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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.
Which of the following statements best describes Cushing's syndrome?
- A. Cushing's syndrome refers to a disease process caused by abnormally high levels of cortisol
- B. Cushing's syndrome refers to a disease process caused by abnormally low levels of aldosterone
- C. Cushing's syndrome refers to a disease process caused by abnormally high levels of aldosterone
- D. Cushing's syndrome refers to a disease process caused by abnormally low levels of cortisol
Correct Answer: A
Rationale: Cushing's syndrome is a condition characterized by excessive levels of cortisol in the body. Cortisol is a hormone produced by the adrenal glands that helps regulate various bodily functions, including metabolism, immune response, and stress response. When there is an overproduction of cortisol, either due to excessive production by the adrenal glands or prolonged use of corticosteroid medications, it can result in Cushing's syndrome. Symptoms of Cushing's syndrome include weight gain, particularly in the face and abdomen, high blood pressure, muscle weakness, and irregularities in menstruation. It is important to diagnose and manage Cushing's syndrome to prevent potential complications such as diabetes, osteoporosis, and cardiovascular disease.
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 of the following is the underlying problem in neurogenic diabetes insipidus?
- A. Overproduction of vasopressin (antidiuretic hormone)
- B. Lack of oxytocin
- C. Overproduction of oxytocin
- D. Overproduction of prolactin
Correct Answer: E
Rationale: Neurogenic diabetes insipidus is a condition characterized by a deficiency of vasopressin (antidiuretic hormone). Vasopressin is responsible for regulating the body's water balance by controlling the reabsorption of water in the kidneys. In neurogenic diabetes insipidus, there is a problem with either the production, release, or action of vasopressin, leading to excessive urination and thirst. This condition can be caused by damage to the hypothalamus or pituitary gland, which are involved in producing and releasing vasopressin. Symptoms of neurogenic diabetes insipidus include frequent urination, excessive thirst, and dehydration.
In males which hormone stimulates Leydig cells to produce testosterone?
- A. Follicle stimulating hormone (FSH)
- B. Luteinizing hormone (LH)
- C. hormone
- D. insipidus
Correct Answer: B
Rationale: In males, Leydig cells in the testes are stimulated to produce testosterone by luteinizing hormone (LH). LH is produced by the anterior pituitary gland and acts on the Leydig cells to promote the synthesis and release of testosterone. This hormone plays a crucial role in male reproductive function and the development of masculine characteristics. Follicle stimulating hormone (FSH) plays a role in spermatogenesis in males but does not directly stimulate Leydig cells to produce testosterone.