Nursing Elites

1. During a healthy heartbeat, the P wave on an ECG represents

• A. The repolarization of the ventricles.
• B. The electrical conduction through the AV node.
• C. The contraction phase of the ventricles (systole).
• D. The depolarization of the atria.

Correct answer: D

Rationale: The P wave on an ECG represents the depolarization of the atria. This electrical activity initiates the contraction of the atria, allowing blood to be pumped into the ventricles. The P wave is the first positive deflection seen on the ECG and signifies the beginning of atrial depolarization, which is a critical step in the cardiac cycle. Choices A, B, and C are incorrect. Option A (The repolarization of the ventricles) is represented by the T wave on the ECG. Option B (The electrical conduction through the AV node) is not represented by the P wave but rather by the PR interval on the ECG. Option C (The contraction phase of the ventricles (systole)) is more related to the QRS complex on the ECG, which represents ventricular depolarization and contraction.

2. Which type of muscle tissue has a unique branching network and is found in the heart?

• A. Skeletal muscle
• B. Cardiac muscle
• C. Smooth muscle
• D. Multifidus muscle

Correct answer: B

Rationale: The correct answer is B, Cardiac muscle. Cardiac muscle is the type of muscle tissue that has a unique branching network and is found in the heart. This type of muscle is involuntary and contracts rhythmically to pump blood throughout the body. Skeletal muscle, choice A, is attached to bones and is responsible for voluntary movements. Smooth muscle, choice C, is found in the walls of internal organs and blood vessels, playing a role in involuntary movements. Multifidus muscle, choice D, is a specific muscle in the back that helps with spinal stability, unrelated to the unique branching network found in cardiac muscle.

3. Which of the following meninges is a thin membrane containing numerous nerves and blood vessels that supply nourishment to the underlying brain cells and spinal cord?

• A. Arachnoid mater
• B. Dura mater
• C. Periosteum
• D. Pia mater

Correct answer: D

Rationale: The pia mater is the correct answer. It is a thin, innermost layer of the meninges that contains numerous nerves and blood vessels, providing nourishment to the underlying brain cells and spinal cord. The arachnoid mater (Choice A) is the middle layer of the meninges and does not contain as many nerves and blood vessels as the pia mater. The dura mater (Choice B) is the tough, outermost layer of the meninges and is not responsible for supplying nourishment. The periosteum (Choice C) is a connective tissue membrane covering bones, not part of the meninges.

4. How many grams of solid CaCO3 are needed to make 600 mL of a 35 M solution? The atomic masses for the elements are as follows: Ca = 40.1 g/mol; C = 12.01 g/mol; O = 16.00 g/mol.

• A. 18.3 g
• B. 19.7 g
• C. 21.0 g
• D. 24.2 g

Correct answer: B

Rationale: 1. First, calculate the molar mass of CaCO3 by adding the atomic masses of Ca, C, and 3 O atoms: 40.1 + 12.01 + (3 * 16.00) = 100.13 g/mol. 2. Calculate the number of moles in 600 mL of a 35 M solution: 600 mL * 35 mol/L = 21,000 mmol. 3. Convert moles to grams using the molar mass of CaCO3: 21,000 mmol * (100.13 g/mol / 1000 mmol/mol) = 2,102.73 g. 4. Therefore, you would need 19.7 g of solid CaCO3 to make 600 mL of a 35 M solution.

5. Which class of hormones is most likely to be released after a serious injury?

• A. Acetylcholine
• B. Oxytocin
• C. Luteinizing hormone
• D. Endorphins

Correct answer: D

Rationale: Endorphins are the class of hormones most likely to be released after a serious injury. Endorphins are the body's natural pain relievers and are produced in response to stress or pain, helping to alleviate discomfort and promote a sense of well-being. Acetylcholine is a neurotransmitter, not a hormone. Oxytocin is mainly involved in childbirth and lactation. Luteinizing hormone is involved in reproductive functions such as ovulation. Therefore, choices A, B, and C are incorrect in the context of a hormone release following a serious injury.

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