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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Mole for mole, which of the following has the greatest effect on plasma osmolality?
- A. Progesterone
- B. Cortisol
- C. Vasopressin
- D. Aldosterone
Correct Answer: C
Rationale: Plasma osmolality is primarily regulated by the concentration of solutes in the blood. Vasopressin, also known as antidiuretic hormone (ADH), plays a key role in regulating water reabsorption in the kidneys, thus affecting plasma osmolality. When plasma osmolality increases, vasopressin is released to increase water reabsorption, leading to a decrease in plasma osmolality. Progesterone, cortisol, and aldosterone do not directly influence water reabsorption and therefore do not have as significant an impact on plasma osmolality as vasopressin.
Cushing syndrome:
- A. may be caused by steroid (prednisone) therapy.
- B. is caused by adrenal insufficiency.
- C. is characterized by hypoglycemia and low blood volume.
- D. is treated with growth hormone.
Correct Answer: A
Rationale: The correct answer is A because Cushing syndrome is typically caused by prolonged exposure to high levels of cortisol, which can result from steroid therapy like prednisone. This leads to symptoms such as weight gain, high blood pressure, and muscle weakness. Adrenal insufficiency (B) is actually the opposite condition. Cushing syndrome is characterized by hyperglycemia and increased blood volume, making choices C incorrect. Growth hormone is not a primary treatment for Cushing syndrome, making choice D incorrect.
Mrs. A., a 50-year-old female, has had symptoms of Cushing syndrome for several years. Mrs. A. states she is 5'5\ tall and weighs 160 lb but the nurse who measured and weighed Mrs. A. states she is only 5' tall. What is the best explanation for this discrepancy?"
- A. Mrs. A. is old and forgetful
- B. Mrs. A. has had previous back surgery
- C. The nurse has measured Mrs. A. incorrectly
- D. Osteoporosis and kyphosis have caused height loss
Correct Answer: D
Rationale: Osteoporosis and kyphosis are common in patients with Cushing syndrome, leading to a loss of height.
Nervousness, increased body temperature, and increased blood-pressure are indications of _______.
- A. diabetes mellitus
- B. hypoglycemia
- C. hypothyroidism
- D. hyperthyroidism
Correct Answer: D
Rationale: The correct answer is D: hyperthyroidism. Nervousness, increased body temperature, and increased blood pressure are classic symptoms of hyperthyroidism. This condition is characterized by an overactive thyroid gland, leading to an excess production of thyroid hormones. These hormones can cause an increase in metabolism, leading to symptoms such as nervousness, heat intolerance, and elevated heart rate. Diabetes mellitus (A) is not associated with increased body temperature or blood pressure. Hypoglycemia (B) is characterized by low blood sugar levels, leading to symptoms such as dizziness and confusion, not increased body temperature. Hypothyroidism (C) is characterized by an underactive thyroid gland, leading to symptoms such as fatigue, weight gain, and cold intolerance, not increased body temperature or blood pressure.
During discharge teaching for the patient with Addison's disease, which statement by the patient indicates that the nurse needs to do additional teaching?
- A. I should always call the doctor if I develop vomiting or diarrhea.
- B. If my weight goes down, my dosage of steroid is probably too high.
- C. I should double or triple my steroid dose if I undergo rigorous physical exercise.
- D. I need to carry an emergency kit with injectable hydrocortisone in case I can't take my medication by mouth.
Correct Answer: B
Rationale: A decrease in weight does not typically indicate that steroid dosage is too high; the patient should understand how to adjust steroids for illness, stress, or physical activity.