Nokea
Organophosphate insecticides and nerve gases exert their lethal effects by:
- A. Blocking alpha and β-adrenergic receptors
- B. Blocking all muscarinic receptors on target cells
- C. Blocking nicotinic receptors in the brain
- D. Inhibiting acetylcholine metabolism
Correct Answer: D
Rationale: The correct answer is D because organophosphate insecticides and nerve gases inhibit acetylcholine metabolism by irreversibly binding to acetylcholinesterase enzyme, leading to accumulation of acetylcholine at synapses. This results in overstimulation of cholinergic receptors, causing symptoms of cholinergic toxicity.
Choice A is incorrect because alpha and beta-adrenergic receptors are not the targets of organophosphates. Choice B is incorrect because organophosphates do not block all muscarinic receptors. Choice C is incorrect because organophosphates do not specifically target nicotinic receptors in the brain.
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Regarding bilirubin:
- A. unconjugated bilirubin is more soluble than conjugated
- B. all conjugated bilirubin is excreted via the intestine
- C. bile duct obstruction causes jaundice secondary to unconjugated hyperbilirubinaemia
- D. haemolytic anaemia may cause ?????? hyperbilirubinaemia
Correct Answer: D
Rationale: The correct answer is D because in hemolytic anemia, there is an increased breakdown of red blood cells, leading to excess bilirubin production. This results in unconjugated hyperbilirubinemia. Unconjugated bilirubin is less soluble than conjugated bilirubin (Choice A). Conjugated bilirubin is excreted via the bile into the intestine, but not all of it is excreted in this manner (Choice B). Bile duct obstruction typically leads to conjugated hyperbilirubinemia, not unconjugated (Choice C).
A patient with hypothyroidism is treated with levothyroxine (Synthroid). What should the nurse include when teaching the patient about this therapy?
- A. Explain that alternate-day dosage may be used if side effects occur.
- B. Provide written instruction for all information related to the drug therapy.
- C. Assure the patient that a return to normal function will occur with replacement therapy.
- D. Inform the patient that the drug must be taken until the hormone balance is reestablished.
Correct Answer: B
Rationale: Providing written instructions helps ensure the patient understands the treatment plan, including correct dosage, administration, and any potential side effects.
How do hormones from the thyroid and parathyroid regulate the calcium concentration of the blood?
- A. Calcitonin lowers blood calcium; parathyroid hormone raises blood calcium.
- B. Parathyroid hormone lowers blood calcium; calcitonin raises blood calcium.
- C. Thyroxine and triiodothyronine together regulate calcium levels, as needs dictate.
- D. Both parathroid hormone and the three thyroid hormones function to regulate blood calcium levels.
Correct Answer: A
Rationale: Step 1: Calcitonin is secreted by the thyroid gland and lowers blood calcium levels by promoting calcium deposition in bones.
Step 2: Parathyroid hormone (PTH) is secreted by the parathyroid gland and raises blood calcium levels by stimulating bone resorption and increasing calcium reabsorption in the kidneys.
Step 3: Since Calcitonin lowers blood calcium and PTH raises blood calcium, choice A is correct.
Summary: Choices B, C, and D are incorrect as they provide inaccurate information about the roles of calcitonin, PTH, thyroxine, and triiodothyronine in regulating blood calcium levels.
Gonadocorticoid(s) ________.
- A. synthesized by the adrenal medulla are primarily androgens
- B. production by the adrenal gland is insignificant compared with sex hormone release from the gonads during late puberty
- C. secretion inhibition is highly dependent on a negative feedback loop involving ACTH
- D. hypersecretion can result in adrenogenital syndrome, also called feminization
Correct Answer: B
Rationale: The correct answer is B because during late puberty, the production of sex hormones by the gonads significantly outweighs the production of gonadocorticoids by the adrenal gland. This is due to the maturation and increased activity of the gonads during this developmental stage.
Rationale:
A: Synthesized by the adrenal medulla are primarily catecholamines, not androgens.
C: Secretion inhibition of gonadocorticoids is primarily regulated by the renin-angiotensin-aldosterone system, not solely by a negative feedback loop involving ACTH.
D: Hypersecretion of gonadocorticoids can lead to conditions like Cushing's syndrome, not adrenogenital syndrome or feminization.
Which disease can be caused by a lack of vitamin C?
- A. AIDS
- B. coronary heart disease
- C. rickets
- D. scurvy
Correct Answer: D
Rationale: The correct answer is D: scurvy. Scurvy is caused by a deficiency of vitamin C, leading to symptoms such as fatigue, bleeding gums, and skin discoloration. Vitamin C is essential for collagen synthesis, and its deficiency impairs collagen formation.
A: AIDS is caused by the human immunodeficiency virus (HIV), not by a lack of vitamin C.
B: Coronary heart disease is primarily related to factors such as high cholesterol, high blood pressure, and smoking, not vitamin C deficiency.
C: Rickets is caused by a deficiency of vitamin D, leading to soft and weak bones, not by a lack of vitamin C.