A student asked the pharmacology instructor to describe the function of a cholinergic agonist.
What would be the instructor’s reply?
Cholinergic agonist decreases the activity of gamma-aminobutyric acid (GABA) receptor sites throughout the body.
Cholinergic agonist decreases the activity of norepinephrine throughout the body.
Cholinergic agonist increases the activity of dopamine receptor sites throughout the brain and spinal cord.
Cholinergic agonist increases the activity of acetylcholine receptor sites throughout the body.
The Correct Answer is D
Choice A rationale
This choice is incorrect. Cholinergic agonists primarily affect acetylcholine receptors, not GABA receptors. GABA receptors are involved in the inhibitory neurotransmission in the central nervous system and are the target of different drug classes, such as benzodiazepines and barbiturates, which are not related to cholinergic agonists.
Choice B rationale
This choice is incorrect. Cholinergic agonists do not decrease norepinephrine activity. Norepinephrine is a neurotransmitter involved in the sympathetic nervous system response, which is different from the cholinergic system. Drugs that decrease norepinephrine activity would have a different mechanism of action, such as adrenergic antagonists.
Choice C rationale
This choice is incorrect. The primary action of cholinergic agonists is not to increase dopamine activity. Dopamine is another neurotransmitter involved in various brain functions, including reward and motor control. Cholinergic agonists specifically target acetylcholine receptors, enhancing their activity, which is not related to dopamine receptors.
Choice D rationale
This choice is correct. Cholinergic agonists increase the activity of acetylcholine receptor sites throughout the body. These drugs mimic the action of acetylcholine, a neurotransmitter that plays a key role in the parasympathetic nervous system, which regulates functions such as muscle contraction, gland secretion, and heart rate. Enhancing acetylcholine activity helps in conditions like myasthenia gravis and certain types of glaucoma.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Choice A rationale
This choice is incorrect. A complete occlusion of a coronary vessel results in a myocardial infarction (heart attack), not unstable angina. Unstable angina occurs when there is a significant narrowing or partial blockage of a coronary artery, leading to reduced blood flow and oxygen supply to the heart muscle, causing pain or discomfort. Complete occlusion would cause permanent damage to the heart muscle, which is not the case with unstable angina.
Choice B rationale
This choice is correct. While unstable angina is mainly caused by narrowing of the coronary arteries, it can also be caused by a spasm of the blood vessel. This spasm, also known as vasospasm, reduces the amount of blood flow to the heart muscle, resulting in pain. These spasms can occur even if the coronary arteries do not have significant plaque buildup, adding another layer of complexity to the condition.
Choice C rationale
This choice is partially correct. The body’s response to a lack of oxygen (ischemia) in the heart muscle does result in pain, known as angina. However, this choice does not fully capture the specific nature of unstable angina, which involves episodes of pain that occur more frequently and are more severe than those associated with stable angina, and can occur at rest or with minimal exertion, indicating a higher risk for a heart attack.
Choice D rationale
This choice is correct. Unstable angina is characterized by a serious narrowing of a coronary artery that reduces oxygen supply to the heart. This narrowing is typically due to atherosclerotic plaque and can be complicated by blood clots or spasms. Unlike stable angina, the pain of unstable angina is more unpredictable and can occur without a triggering factor like exercise or stress, signaling a higher risk of a heart attack.
Correct Answer is A
Explanation
Choice A rationale
Oral morphine typically reaches peak activity at around 45 minutes after administration. This allows time for the medication to be absorbed through the gastrointestinal tract and enter the bloodstream to provide pain relief.
Choice B rationale
10 minutes is too short for oral morphine to reach peak activity. This timeframe is more consistent with intravenous administration, which allows for rapid onset of action.
Choice C rationale
30 minutes is a bit too short for oral morphine to reach peak effect, although some patients may start to feel relief. However, peak plasma concentrations generally occur closer to 45-60 minutes.
Choice D rationale
While morphine can continue to have effects up to 60 minutes and beyond, the peak activity is typically observed around the 45-minute mark. Waiting for 60 minutes may underestimate the peak timeframe.
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