Nokea
Insulin and glucagon:
- A. are secreted by the beta cells of the islets of Langerhans.
- B. elevate blood glucose levels.
- C. are secreted in response to declining plasma levels of glucose.
- D. are secreted by the pancreas to regulate blood glucose.
Correct Answer: D
Rationale: The correct answer is D because insulin and glucagon are both hormones secreted by the pancreas to regulate blood glucose levels. Insulin is secreted by beta cells in response to high blood glucose levels, promoting glucose uptake by cells. Glucagon is secreted by alpha cells in response to low blood glucose levels, stimulating the release of stored glucose. Choices A and C are incorrect because insulin is secreted by beta cells, not glucagon, and they are secreted in response to high, not low, glucose levels. Choice B is incorrect because insulin lowers blood glucose levels, while glucagon raises them.
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Which gland is located just superior to the kidneys?
- A. Pituitary
- B. Adrenal
- C. Pancreas
- D. Ovary
Correct Answer: B
Rationale: The correct answer is B: Adrenal gland. The adrenal gland is located just superior to the kidneys. It is part of the endocrine system and plays a crucial role in producing hormones such as cortisol and adrenaline. The pituitary gland (A) is located in the brain, the pancreas (C) is situated in the abdomen, and the ovaries (D) are found in the pelvic region. The adrenal gland's location and function make it the most appropriate choice in this scenario.
The secretions from which of these glands differs between males and females?
- A. Adrenal.
- B. Parathyroid.
- C. Gonadal.
- D. Pancreas.
Correct Answer: C
Rationale: The correct answer is C: Gonadal glands. These glands differ between males and females in terms of the hormones they secrete. In males, the gonadal glands (testes) produce testosterone, while in females, the gonadal glands (ovaries) produce estrogen and progesterone. Adrenal glands (A) secrete hormones like cortisol and adrenaline, which are not gender-specific. Parathyroid glands (B) regulate calcium levels and are not gender-specific. Pancreas (D) secretes insulin and glucagon, which are also not gender-specific. Therefore, the key difference in secretions between males and females lies in the gonadal glands.
Which of the following hormones exerts negative feedback control on the secretion of ACTH?
- A. PTH
- B. Glucagon
- C. Cortisol
- D. Corticotrophin-releasing hormone
Correct Answer: C
Rationale: The correct answer is C: Cortisol. Cortisol exerts negative feedback control on the secretion of ACTH by inhibiting the release of corticotrophin-releasing hormone (CRH) and ACTH from the hypothalamus and pituitary gland, respectively. This feedback loop helps regulate the body's stress response and maintain hormone levels within a normal range.
A: PTH (Parathyroid Hormone) does not directly regulate the secretion of ACTH.
B: Glucagon regulates blood sugar levels and does not directly affect ACTH secretion.
D: Corticotrophin-releasing hormone (CRH) is the hormone that stimulates the release of ACTH, so it does not exert negative feedback control on ACTH secretion.
An example of a hormone that under certain circumstances is regulated by positive feedback is:
- A. calcitonin.
- B. histamine.
- C. oxytocin.
- D. melatonin.
Correct Answer: C
Rationale: Rationale:
1. Oxytocin is released during childbirth to stimulate uterine contractions.
2. As contractions increase, oxytocin secretion is further stimulated in a positive feedback loop.
3. This positive feedback mechanism amplifies the contractions until delivery.
4. Calcitonin regulates calcium levels, histamine is involved in allergic responses, and melatonin regulates sleep-wake cycles.
Summary:
- Calcitonin, histamine, and melatonin do not exhibit positive feedback regulation like oxytocin during childbirth.
A patient has been receiving a large dose of prednisone for the relief of arthritic pain for 6 months. He suddenly stops taking his medication. What is the most serious concern?
- A. His arthritic pain will recur.
- B. He will develop an acute adrenal insufficiency.
- C. He will continue to exhibit symptoms of Cushing syndrome.
- D. He will develop a moon face and buffalo hump.
Correct Answer: B
Rationale: The correct answer is B: He will develop an acute adrenal insufficiency. When a patient abruptly stops taking a large dose of prednisone after long-term use, it can suppress the body's natural production of cortisol. This sudden withdrawal can lead to adrenal insufficiency, a potentially life-threatening condition. The adrenal glands may not be able to produce enough cortisol to meet the body's needs, causing symptoms such as fatigue, weakness, low blood pressure, and even shock. This is a serious concern that requires medical attention.
Incorrect choices:
A: His arthritic pain will recur - While this is a valid concern, it is not the most serious issue compared to acute adrenal insufficiency.
C: He will continue to exhibit symptoms of Cushing syndrome - Cushing syndrome is a result of prolonged exposure to high levels of cortisol, not sudden withdrawal.
D: He will develop a moon face and buffalo hump - These are physical symptoms associated with Cushing syndrome, not acute adrenal