Nokea
Which sequence is part of the life cycle of a very large mass star?
- A. red giant → planetary nebula + neutron star
- B. red giant → planetary nebula + black hole
- C. red supergiant → supernova → neutron star
- D. red supergiant → supernova → black hole
Correct Answer: D
Rationale: The correct answer is D: red supergiant → supernova → black hole. This sequence is part of the life cycle of a very large mass star. Red supergiants are massive stars in the later stages of their evolution. When a red supergiant goes supernova, it explodes in a massive stellar explosion, leaving behind a remnant that can collapse into a black hole due to the immense gravitational forces. Choices A and B are incorrect because planetary nebulae form from the outer layers of lower mass stars, not very large mass stars. Choice C is incorrect as neutron stars are more likely to form from the remnants of less massive stars.
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Adrenaline combination with local anesthetics has the following effects EXCEPT:
- A. Reduces the absorption of local anesthetic
- B. Increases the duration of its local anesthetic activity
- C. Decreases the toxicity of the local anesthetic
- D. Increases blood flow to the injection area
Correct Answer: D
Rationale: Correct Answer: D. Increases blood flow to the injection area.
Rationale:
1. Adrenaline is a vasoconstrictor that reduces blood flow in the injection area.
2. By constricting blood vessels, adrenaline limits the absorption of the local anesthetic, leading to prolonged local action.
3. Adrenaline also helps in reducing the systemic toxicity of the local anesthetic by limiting its absorption.
4. Therefore, the correct answer is D as adrenaline does not increase blood flow to the injection area.
When blood glucose levels are low, the ______ will increase the secretion of ______.
- A. adrenal cortex: aldosterone
- B. pancreas; glucagon
- C. pancreas: insulin
- D. posterior pituitary: ADH
Correct Answer: B
Rationale: The correct answer is B: pancreas; glucagon. When blood glucose levels are low, the pancreas secretes glucagon. Glucagon acts to increase blood glucose levels by stimulating the liver to release stored glucose. The adrenal cortex does not directly regulate blood glucose levels through aldosterone secretion. Insulin is secreted by the pancreas in response to high blood glucose levels to lower them, not increase them. The posterior pituitary secretes ADH to regulate water balance, not blood glucose levels.
The following statements concerning prazosin and phentolamine are correct EXCEPT:
- A. Both antagonize alpha1-receptors
- B. Both cause the same degree of tachycardia
- C. Both decrease blood pressure
- D. Both are competitive antagonists
Correct Answer: B
Rationale: Correct Answer: B
Rationale:
1. Prazosin and phentolamine both antagonize alpha1-receptors, leading to vasodilation and decreased blood pressure.
2. Both drugs are competitive antagonists, competing with norepinephrine at alpha1-receptors.
3. However, phentolamine causes reflex tachycardia due to its non-selective alpha-adrenergic blockade, unlike prazosin.
4. Therefore, the statement that both cause the same degree of tachycardia is incorrect based on their pharmacological differences.
Addison's disease frequently causes skin pigment changes. When teaching the patient about medications used for Addison's disease, it is important that he or she understands:
- A. To take plenty of water (at least 8 ounces or 240 mL) with the medication.
- B. Proper subcutaneous injection technique.
- C. That they continue for life.
- D. That they can be stopped when symptoms abate.
Correct Answer: C
Rationale: Patients with Addison's disease require lifelong hormone replacement therapy to manage the condition as the adrenal glands do not produce enough cortisol.
Which of the following posterior pituitary hormones causes the kidney to decrease its excretion of urine?
- A. ADH
- B. ACTH
- C. Aldosterone
- D. Oxytocin
Correct Answer: A
Rationale: Correct answer: A (ADH)
Rationale:
1. ADH (Antidiuretic hormone) acts on the kidneys to increase water reabsorption, leading to decreased urine output.
2. ACTH (Adrenocorticotropic hormone) stimulates the adrenal glands, not the kidneys.
3. Aldosterone acts on the kidneys to regulate electrolyte balance, not directly affecting urine volume.
4. Oxytocin primarily functions in uterine contractions and milk ejection, not in kidney function.