Nokea
Regarding phosphorylase:
- A. it clea???? 1:6α linkages in glycogen
- B. it is activated by norepinephrine
- C. phosphorylase kinase is directly activated by cyclic AMP
- D. activation of protein kinase A inhibits glycogen synthesis
Correct Answer: D
Rationale: Step 1: Activation of protein kinase A leads to phosphorylation of phosphorylase kinase.
Step 2: Phosphorylase kinase phosphorylates and activates phosphorylase.
Step 3: Active phosphorylase cleaves 1,4-glycosidic linkages in glycogen, not 1,6 linkages (eliminates A).
Step 4: Phosphorylase is activated by phosphorylase kinase, not norepinephrine (eliminates B and C).
Step 5: Inhibition of glycogen synthesis occurs when phosphorylase is activated, supporting choice D as the correct answer.
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α-1 adrenergic receptors are selectively blocked by:
- A. Phentolamine
- B. Prazosin
- C. Propranolol
- D. Ergotamine
Correct Answer: B
Rationale: The correct answer is B: Prazosin. α-1 adrenergic receptors are selectively blocked by prazosin. Prazosin is a selective α-1 adrenergic receptor antagonist, specifically targeting these receptors. It works by blocking the effects of norepinephrine, leading to vasodilation and reduced blood pressure.
A: Phentolamine is a non-selective α-adrenergic receptor antagonist, blocking both α-1 and α-2 receptors.
C: Propranolol is a non-selective β-adrenergic receptor antagonist, blocking β-1 and β-2 receptors.
D: Ergotamine is a medication used for the treatment of migraines and has vasoconstrictive properties but does not selectively block α-1 adrenergic receptors.
A client is admitted to the hospital with Addison's disease. When discharging the client, the nurse reviews discharge instructions on nutrition. Which of the following discharge instructions are important for the client with Addison's disease regarding nutrition?
- A. Eat a diet high in protein, low in refined carbohydrates
- B. Consume two meals per day
- C. Eat foods high in potassium
- D. Drink less than 1 L of fluid per day
Correct Answer: A
Rationale: A diet high in protein and low in refined carbohydrates is important for clients with Addison's disease to support adrenal function and manage their condition.
Neostigmine is a drug useful in the treatment of myasthenia gravis, but it causes parasympathomimetic effects unless another drug is given first. This drug is:
- A. Atropine
- B. Epinephrine
- C. Isoproterenol
- D. Edrophonium
Correct Answer: A
Rationale: The correct answer is A: Atropine. Neostigmine is a cholinesterase inhibitor that increases acetylcholine levels leading to parasympathomimetic effects. Atropine, an anticholinergic drug, blocks the effects of acetylcholine, preventing excessive stimulation of cholinergic receptors. Administering atropine before neostigmine helps counteract the parasympathomimetic effects, making it a necessary pre-treatment. Epinephrine and isoproterenol are adrenergic drugs and wouldn't counteract the cholinergic effects of neostigmine. Edrophonium is another cholinesterase inhibitor like neostigmine, so it wouldn't be effective in preventing the parasympathomimetic effects.
In Which of the Following Pairs, the Hormone of Endocrine Glands and Its Primary Action Is Incorrect or Mismatched?
- A. Calcitonin - Lower blood calcium levels
- B. Parathyroid - Raises blood calcium levels
- C. Somatostatin - Inhibits release of glucagon
- D. Melatonin - Regulates the rate of cellular metabolism
Correct Answer: D
Rationale: The correct answer is D - Melatonin - Regulates the rate of cellular metabolism. Melatonin is a hormone primarily involved in regulating sleep-wake cycles, not cellular metabolism.
A: Calcitonin - Lower blood calcium levels - Correct. Calcitonin is released by the thyroid gland to lower blood calcium levels.
B: Parathyroid - Raises blood calcium levels - Correct. Parathyroid hormone is released by the parathyroid glands to raise blood calcium levels.
C: Somatostatin - Inhibits release of glucagon - Correct. Somatostatin inhibits the release of glucagon and insulin.
The element essential for normal thyroid function is:
- A. Potassium
- B. Sodium
- C. Iodine
- D. Calcium
Correct Answer: C
Rationale: The correct answer is C: Iodine. Iodine is essential for the production of thyroid hormones T3 and T4. These hormones regulate metabolism, growth, and development. Potassium (A), Sodium (B), and Calcium (D) do not play a direct role in thyroid function. Potassium and Sodium are electrolytes important for nerve function and fluid balance, while Calcium is crucial for bone health and muscle function. Therefore, the correct answer is Iodine as it is specifically required for normal thyroid function.