How does ephedrine act on the body?
Acts directly on alpha-Adrenergic receptor sites
Stimulates the release of norepinephrine
Acts directly on Beta-Adrenergic receptor sites
Stimulates the release of Dopamine
The Correct Answer is B
A) Acts directly on alpha-adrenergic receptor sites: Ephedrine does not act exclusively or directly on alpha-adrenergic receptors. While it can have some alpha-adrenergic effects, its primary mechanism is through the release of norepinephrine, which then activates both alpha and beta receptors. Therefore, this option is not entirely accurate for describing ephedrine's mode of action.
B) Stimulates the release of norepinephrine: Ephedrine primarily works by stimulating the release of norepinephrine from nerve terminals. The released norepinephrine then acts on both alpha and beta adrenergic receptors, leading to vasoconstriction (via alpha receptors) and increased heart rate and force of contraction (via beta receptors). This dual action helps raise blood pressure and improve cardiac output, making this the most accurate description of ephedrine's mechanism of action.
C) Acts directly on beta-adrenergic receptor sites: Although ephedrine does have beta-adrenergic effects (increasing heart rate and contractility), its primary mechanism is the indirect release of norepinephrine. It does not act directly on beta-receptors to the same extent as medications like isoproterenol. Therefore, while it does have beta-receptor activity, the main action is through norepinephrine release.
D) Stimulates the release of dopamine: Ephedrine does not primarily stimulate dopamine release. Dopamine release is more associated with drugs like levodopa or certain dopaminergic agents used in conditions like Parkinson’s disease. Ephedrine primarily affects norepinephrine and, to a lesser extent, acts on dopamine receptors, but it is not primarily a dopamine-releasing agent.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
A) Phagocytosis: Phagocytosis refers to the process by which a cell engulfs large particles, such as pathogens or debris, and brings them into the cell. It is not related to the movement of hormones across the cell membrane.
B) Endocytosis: Endocytosis is the process where a cell engulfs substances from the external environment and brings them into the cell. However, this term is typically used when substances like nutrients or larger molecules are taken into the cell, not when hormones are being secreted out of the cell.
C) Pinocytosis: Pinocytosis is a type of endocytosis in which the cell engulfs extracellular fluid and dissolved substances. It is often referred to as "cell drinking" and involves the uptake of fluids, not the secretion of hormones across the membrane.
D) Exocytosis: This is the correct answer. Exocytosis is the process by which substances, such as hormones or neurotransmitters, are transported from inside the cell to the outside by vesicles that fuse with the cell membrane. In the case of hormones, they are synthesized within the cell and then released into the extracellular space via exocytosis, enabling them to reach their target sites.
Correct Answer is D
Explanation
A) Reversal of bronchoconstriction: Narcotic antagonists are not used to reverse bronchoconstriction. Bronchoconstriction is typically managed with bronchodilators (such as beta-agonists) or corticosteroids. Narcotic antagonists, such as naloxone, specifically counteract the effects of opioids, not respiratory conditions like bronchoconstriction.
B) Reversal of tachycardia: Narcotic antagonists do not have an effect on reversing tachycardia. Tachycardia may result from various conditions, including stimulant use, dehydration, or heart conditions. Treatment for tachycardia typically involves addressing the underlying cause, such as using beta-blockers for cardiac issues, but not narcotic antagonists.
C) Treatment of alcohol dependence: While certain medications, like disulfiram or acamprosate, are used to treat alcohol dependence, narcotic antagonists are not typically indicated for alcohol dependence. Narcotic antagonists, such as naloxone, are primarily used for opioid overdose or dependence, not for alcohol use disorders.
D) Treatment of narcotic dependence: Narcotic antagonists, such as naloxone, are prescribed in the treatment of narcotic (opioid) dependence. These medications work by blocking the effects of opioids at the receptor sites, thereby preventing the "high" associated with opioid use. They are particularly useful in treating opioid overdoses and can also be used in the management of opioid addiction as part of a comprehensive treatment plan.
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