What is the main function of the Na-K pump at the cellular level?
Move Na inside the cell
Move K out of the cell
Move Na out of the cell
Move Na and K inside the cell
The Correct Answer is C
Choice A: Move Na Inside the Cell
The primary function of the Na-K pump, also known as the sodium-potassium pump, is to move sodium (Na) ions out of the cell, not into the cell. This pump actively transports three sodium ions out of the cell for every two potassium ions it brings in. Therefore, this choice is incorrect.
Choice B: Move K Out of the Cell
The Na-K pump moves potassium (K) ions into the cell, not out of the cell. This active transport mechanism helps maintain the necessary concentration gradients of sodium and potassium across the cell membrane, which are crucial for various cellular functions, including maintaining the resting membrane potential.
Choice C: Move Na Out of the Cell
The main function of the Na-K pump is to move sodium ions out of the cell. For every cycle of the pump, three sodium ions are exported out of the cell, and two potassium ions are imported into the cell. This process is essential for maintaining the electrochemical gradient across the cell membrane, which is vital for nerve impulse transmission, muscle contraction, and overall cellular homeostasis.
Choice D: Move Na and K Inside the Cell
This choice is incorrect because the Na-K pump does not move both sodium and potassium ions inside the cell. Instead, it moves sodium ions out of the cell and potassium ions into the cell. This active transport mechanism is crucial for maintaining the proper ionic balance and membrane potential necessary for various physiological processes.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is C
Explanation
Choice A: Alkalosis
Alkalosis refers to a condition where the blood pH is higher than the normal range (above 7.45). In this case, the pH is 7.25, which indicates an acidic environment rather than an alkaline one. Therefore, alkalosis is not the correct answer.
Choice B: Respiratory
Respiratory acidosis or alkalosis is determined by the levels of PaCO2. In respiratory acidosis, PaCO2 is elevated, while in respiratory alkalosis, PaCO2 is decreased. Here, the PaCO2 is 20 mm Hg, which is below the normal range, indicating a respiratory component. However, the primary issue is not respiratory because the HCO3- is also significantly low, pointing towards a metabolic cause.
Choice C: Metabolic
Metabolic acidosis is characterized by a low pH and a low HCO3- level. In this case, the pH is 7.25, and the HCO3- is 10 mEq/L, both of which are below the normal ranges. This indicates that the primary acid-base imbalance is metabolic acidosis.
Choice D: Acidosis
Acidosis refers to a condition where the blood pH is lower than the normal range (below 7.35). The given pH of 7.25 confirms that the patient is experiencing acidosis. However, this choice alone does not specify whether it is metabolic or respiratory acidosis.
Choice E: With Compensation (Being Compensated)
Compensation refers to the body’s attempt to return the pH to normal by adjusting the levels of PaCO2 or HCO3-. In this case, the low PaCO2 suggests that there is a respiratory compensation for the metabolic acidosis. However, the primary imbalance remains metabolic acidosis.
Correct Answer is A
Explanation
Choice A: Alpha 1 Agonist and Alpha 2 Antagonist Increase Blood Pressure
Alpha 1 receptors are primarily located on the smooth muscles of blood vessels. When activated by an agonist, these receptors cause vasoconstriction, which increases blood pressure. On the other hand, alpha 2 receptors are found on presynaptic nerve terminals and act to inhibit the release of norepinephrine. An antagonist at alpha 2 receptors would prevent this inhibition, leading to increased norepinephrine release, further promoting vasoconstriction and increasing blood pressure. Therefore, the combination of an alpha 1 agonist and an alpha 2 antagonist would synergistically increase blood pressure.
Choice B: Alpha 1 Agonist and Alpha 2 Agonist Decrease Blood Pressure
Alpha 1 agonists increase blood pressure by causing vasoconstriction. Alpha 2 agonists, however, decrease blood pressure by inhibiting norepinephrine release, leading to vasodilation. Therefore, this combination would not decrease blood pressure as the effects of the alpha 1 agonist would counteract the effects of the alpha 2 agonist.
Choice C: Alpha 1 and Alpha 2 Agonist Increase Blood Pressure
While alpha 1 agonists increase blood pressure through vasoconstriction, alpha 2 agonists actually decrease blood pressure by reducing norepinephrine release. Therefore, this statement is incorrect as the combined effect would not result in an increase in blood pressure.
Choice D: Alpha 1 Antagonist and Alpha 2 Agonist Decrease Blood Pressure
Alpha 1 antagonists block the vasoconstrictive action of alpha 1 receptors, leading to vasodilation and a decrease in blood pressure. Alpha 2 agonists also decrease blood pressure by inhibiting norepinephrine release. Therefore, this combination would indeed decrease blood pressure, making this statement partially correct but not the best answer compared to choice A.
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