Nokea
In relation to amphetamine, all are true EXCEPT:
- A. Indirect acting sympathomimetic
- B. Has prominent CNS action
- C. Chronic use can produce addiction
- D. Acidification of urine decreases its excretion
Correct Answer: D
Rationale: The correct answer is D because acidification of urine actually increases the excretion of amphetamine. Step 1: Amphetamine is an indirect acting sympathomimetic, which means it stimulates the release of norepinephrine. Step 2: It has prominent CNS action by increasing the release of dopamine and norepinephrine, leading to effects like increased alertness and euphoria. Step 3: Chronic use of amphetamine can indeed lead to addiction due to its reinforcing properties and impact on the brain's reward system. Therefore, D is incorrect as acidification of urine does not decrease amphetamine excretion; instead, it can enhance excretion by increasing its solubility in urine.
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Antoinette has gone to her primary care provider for a routine physical. Some of her laboratory results indicated an endocrine disorder. In hyperparathyroidism which test results are typical?
- A. Decreased WBC and increased alkaline phosphatase.
- B. Increased calcium and decreased phosphate.
- C. Decreased PTH and increased magnesium.
- D. Increased PTH and decreased calcium.
Correct Answer: B
Rationale: In hyperparathyroidism, increased parathyroid hormone (PTH) leads to increased calcium levels and decreased phosphate levels in the blood.
The hormone involved in rhythmic activities, such as day/night and seasonal changes, is .
- A. calcitonin
- B. melatonin
- C. estrogen
- D. cyclin
Correct Answer: B
Rationale: The correct answer is B: melatonin. Melatonin is the hormone involved in regulating rhythmic activities like day/night and seasonal changes through its influence on the body's circadian rhythm. Calcitonin is a hormone that regulates calcium levels in the blood; estrogen is a female sex hormone; and cyclin is a protein involved in cell cycle regulation. Melatonin's role in regulating sleep-wake cycles and responding to changes in light exposure makes it the most appropriate choice for a hormone involved in rhythmic activities.
Which of the following is NOT true of cortisol?
- A. It counteracts the inflammatory response.
- B. It promotes the breakdown of proteins to amino acids that the liver uses to convert to glucose.
- C. It promotes metabolism of fatty acids instead of glucose.
- D. It is a mineralocorticoid.
Correct Answer: D
Rationale: Correct Answer: D - It is a mineralocorticoid.
Rationale: Cortisol is a glucocorticoid, not a mineralocorticoid. Glucocorticoids like cortisol regulate glucose metabolism and counteract inflammation, supporting options A and B. Option C is also incorrect as cortisol promotes the metabolism of glucose over fatty acids.
Which equation is used to calculate the power P of the machine?
- A. P = ΔE × t
- B. P = W × t
- C. P = ΔE / t
- D. P = W / ΔE
Correct Answer: C
Rationale: The correct equation for calculating power is P = ΔE / t. Power is defined as the rate at which work is done or energy is transferred. In this equation, ΔE represents the change in energy and t represents the time taken for that change. Dividing the change in energy by the time gives us the power. This equation aligns with the fundamental definition of power.
Choice A (P = ΔE × t) is incorrect because it implies that power is directly proportional to both the change in energy and time, which is not always the case.
Choice B (P = W × t) is incorrect because it incorrectly uses work (W) in the equation for power, while power is specifically related to the rate at which work is done, not the work itself.
Choice D (P = W / ΔE) is incorrect because it suggests power is inversely proportional to the change in energy, which is not a characteristic of power.
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.