Nursing Elites

1. The pH scale is used to indicate the concentration of:

• A. Hydrogen ions
• B. Oxygen
• C. Salts
• D. Sugar molecules

Correct answer: A

Rationale: The pH scale is a measure of the concentration of hydrogen ions in a solution, representing its acidity or basicity. A lower pH value indicates higher hydrogen ion concentration and acidity, while a higher pH value indicates lower hydrogen ion concentration and basicity. Choice A, 'Hydrogen ions,' is the correct answer because the pH scale specifically measures the concentration of hydrogen ions in a solution. Choices B, C, and D are incorrect as the pH scale is not used to indicate the concentration of oxygen, salts, or sugar molecules.

2. How does urine flow through the urethra?

• A. Continuously
• B. Only when the bladder is completely full
• C. Under voluntary control of sphincter muscles
• D. A combination of B and C

Correct answer: C

Rationale: Urine flows through the urethra under voluntary control of sphincter muscles. These muscles can be consciously contracted or relaxed to control the flow of urine from the bladder to the outside of the body. Choice A is incorrect as urine flow is not continuous but rather regulated. Choice B is incorrect because urine flow is not restricted to only when the bladder is completely full. Choice D is incorrect as it inaccurately combines the two incorrect statements of choices B and C.

3. What does the P-wave in an ECG correspond to?

• A. Atrial repolarization
• B. Depolarization of SA node
• C. Ventricular depolarization
• D. Ventricular repolarization

Correct answer: B

Rationale: The P-wave in an ECG represents the depolarization of the SA node and the atria, not atrial repolarization. Choice C, ventricular depolarization, is incorrect because the P-wave does not correspond to ventricular activity. Choice D, ventricular repolarization, is also incorrect as the P-wave does not depict ventricular repolarization. The correct interpretation is that the P-wave signifies the initiation of the electrical impulse at the SA node and subsequent atrial depolarization, making option B the correct answer.

4. Which statement is TRUE about valence electrons?

• A. They are located in the innermost electron shell.
• B. They have the highest binding energy to the nucleus.
• C. They are most likely to participate in chemical bonding.
• D. They have no influence on the element's chemical properties.

Correct answer: C

Rationale: Valence electrons are the outermost electrons in an atom's electron cloud and are crucial in forming chemical bonds with other atoms. These electrons determine the reactivity and chemical properties of an element, making option C the correct statement. Option A is incorrect as valence electrons are found in the outer shell, not the innermost shell. Option B is incorrect because valence electrons have lower binding energy compared to inner electrons. Option D is incorrect since valence electrons play a significant role in an element's chemical behavior.

5. What is a major structure of the limbic system?

• A. Brainstem
• B. Spinal cord
• C. Hypothalamus
• D. Cerebral cortex

Correct answer: C

Rationale: The correct answer is C: Hypothalamus. The hypothalamus is a significant structure of the limbic system responsible for regulating various functions such as emotions, autonomic functions, and hormone production. It plays a crucial role in maintaining homeostasis and orchestrating responses to stress and emotional stimuli. Choices A, B, and D are incorrect. The brainstem, although a vital part of the brain, is not a major structure of the limbic system. The spinal cord is not part of the limbic system; it is primarily involved in transmitting sensory and motor information between the brain and the rest of the body. The cerebral cortex is responsible for higher cognitive functions but is not a major structure within the limbic system.

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