Nursing Elites

1. 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.

2. Which of the following constituents of blood is a biconcave disc that is round and flat without a nucleus?

• A. Plasma
• B. Platelet
• C. RBC
• D. WBC

Correct answer: C

Rationale: The correct answer is C, RBC (Red Blood Cell). Red blood cells are biconcave discs that lack a nucleus, allowing them to carry oxygen efficiently. Plasma (A) is the liquid component of blood that carries various substances. Platelets (B) are cell fragments important for blood clotting. White blood cells (WBCs) (D) are part of the immune system and have a nucleus.

3. Which cells myelinate neurons in the CNS?

• A. Schwann cells
• B. Astrocytes
• C. Microglia
• D. Oligodendrocytes

Correct answer: D

Rationale: The correct answer is D, Oligodendrocytes. Oligodendrocytes are responsible for myelinating neurons in the central nervous system (CNS). Schwann cells, found in the peripheral nervous system, are responsible for myelinating neurons there. Astrocytes support and maintain the neuronal environment, while microglia function as immune cells in the CNS, participating in immune responses and cellular debris clearance. Therefore, choices A, B, and C are incorrect for myelination of CNS neurons.

4. Which protein complex in the sarcomere is responsible for the thick filament?

• A. Actin
• B. Myosin
• C. Tropomyosin
• D. Troponin

Correct answer: B

Rationale: Myosin is the protein complex responsible for the thick filament in the sarcomere. It interacts with actin, another protein in the sarcomere, to generate the sliding movement that results in muscle contraction. Actin is a thin filament protein that interacts with myosin to create the sliding filament mechanism. Tropomyosin and troponin are regulatory proteins that regulate muscle contraction by controlling the interaction between actin and myosin, rather than directly being responsible for the thick filament.

5. Which property of a wave is measured in Hertz (Hz)?

• A. Amplitude
• B. Wavelength
• C. Speed
• D. Frequency

Correct answer: D

Rationale: Frequency is the property of a wave that is measured in Hertz (Hz). It represents the number of complete cycles of the wave that occur in one second. Amplitude refers to the height of the wave, wavelength is the distance between two consecutive points on a wave that are in phase, and speed is the rate at which the wave travels through a medium. Therefore, the correct answer is frequency as it directly corresponds to the unit Hertz (Hz) used to measure the number of wave cycles per second.

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