Nokea
Which statement about the reaction is correct?
- A. It is endothermic and thermal energy is absorbed from the surroundings.
- B. It is endothermic and thermal energy is transferred to the surroundings.
- C. It is exothermic and thermal energy is absorbed from the surroundings.
- D. It is exothermic and thermal energy is transferred to the surroundings.
Correct Answer: A
Rationale: The correct answer is A because an endothermic reaction absorbs thermal energy from the surroundings to proceed. In an endothermic reaction, the products have higher potential energy than the reactants, requiring energy input. Choice B is incorrect as endothermic reactions do not transfer thermal energy to the surroundings. Choices C and D are incorrect as they describe exothermic reactions, where thermal energy is released to the surroundings.
You may also like to solve these questions
Which of the following hormones are responsible for the 'fight-or-flight' response?
- A. Epinephrine and norepinephrine.
- B. Insulin and glucagon.
- C. Esrtogen and progesterone.
- D. Thyroxin and melatonin.
Correct Answer: A
Rationale: The correct answer is A: Epinephrine and norepinephrine. These hormones are released by the adrenal glands during stressful situations to trigger the 'fight-or-flight' response. They increase heart rate, blood pressure, and energy production to prepare the body for action. Insulin and glucagon (B) regulate blood sugar levels. Estrogen and progesterone (C) are female sex hormones. Thyroxin and melatonin (D) are involved in metabolism and sleep regulation, respectively. Therefore, only A directly relates to the physiological response of 'fight-or-flight'.
Two terms that are paired incorrectly are .
- A. cortisol-adrenal cortex
- B. androgens-adrenal cortex
- C. calcitonin-thyroid
- D. corticosteroid-adrenal medulla
Correct Answer: D
Rationale: The correct answer is D because corticosteroids are produced by the adrenal cortex, not the adrenal medulla. Cortisol is a type of corticosteroid, making choice A incorrect. Androgens are indeed produced by the adrenal cortex, making choice B correct. Calcitonin is produced by the thyroid, not the adrenal cortex, making choice C incorrect. Therefore, the only pair that is incorrect is corticosteroid and adrenal medulla.
A patient with Alzheimer's disease is taking an acetylcholinesterase inhibitor specifically approved for that indication, primarily because it is quite lipophilic and so enters the CNS well. Which of the following drugs is the patient most likely receiving?
- A. Donepezil
- B. Edrophonium
- C. Neostigmine
- D. Pyridostigmine
Correct Answer: A
Rationale: The correct answer is A: Donepezil. Donepezil is a lipophilic acetylcholinesterase inhibitor approved for Alzheimer's disease due to its ability to enter the CNS effectively. It enhances cholinergic transmission by inhibiting the enzyme responsible for acetylcholine breakdown. Edrophonium is a short-acting acetylcholinesterase inhibitor used for diagnostic purposes, not for Alzheimer's treatment. Neostigmine and Pyridostigmine are not lipophilic and are primarily used for myasthenia gravis to enhance muscle strength, not for Alzheimer's disease.
The person with _____ is most likely to receive insulin therapy.
- A. myxedema
- B. Graves’ disease
- C. diabetes insipidus
- D. hyperglycemia
Correct Answer: D
Rationale: The correct answer is D: hyperglycemia. Hyperglycemia refers to high blood sugar levels, a hallmark of diabetes mellitus. Insulin therapy is commonly prescribed to individuals with diabetes to help regulate their blood sugar levels. Myxedema (choice A) is associated with hypothyroidism, Graves' disease (choice B) is an autoimmune disorder affecting the thyroid, and diabetes insipidus (choice C) involves the kidneys and has no direct relation to insulin therapy for diabetes. Therefore, hyperglycemia is the most appropriate condition for receiving insulin therapy.
A 43-year-old woman with diagnosed myasthenia gravis presents with profound skeletal muscle weakness. We are unsure whether she is experiencing a cholinergic crisis or a myasthenic crisis, so we administer a usually appropriate dose of parenteral edrophonium. Assume the patient was actually experiencing a cholinergic crisis. Which of the following is the most likely response to the drug?
- A. Hypertensive crisis from peripheral vascular constriction
- B. Myocardial ischemia, and angina, from drug-induced tachycardia and coronary vasoconstriction
- C. Premature ventricular contractions from increased ventricular automaticity
- D. Ventilatory distress or failure
Correct Answer: D
Rationale: The correct answer is D: Ventilatory distress or failure. Edrophonium is a short-acting acetylcholinesterase inhibitor used to differentiate between myasthenic and cholinergic crises. In a cholinergic crisis, which is an excess of acetylcholine, administering edrophonium can worsen symptoms due to further acetylcholine accumulation. This can lead to excessive stimulation of the respiratory muscles, resulting in ventilatory distress or failure.
Choice A is incorrect because cholinergic crisis typically causes hypotension, not hypertension. Choice B is incorrect because edrophonium-induced tachycardia can worsen myocardial ischemia, not angina. Choice C is incorrect because increased ventricular automaticity would not be a common response to edrophonium in a cholinergic crisis.