Nursing Elites

1. What is the small repeating unit in the contractile apparatus of skeletal muscle?

• A. Myofibril
• B. Actin
• C. Sarcomere
• D. Myosin

Correct answer: C

Rationale: The correct answer is 'Sarcomere.' The sarcomere is the smallest repeating unit within myofibrils and is responsible for muscle contraction in skeletal muscle. It consists of overlapping actin and myosin filaments arranged in a highly organized structure that allows for the sliding of filaments during muscle contraction. 'Myofibril' (choice A) is incorrect because it is a larger structure composed of sarcomeres. 'Actin' (choice B) and 'Myosin' (choice D) are incorrect as they are individual proteins that are components of the sarcomere, not the smallest repeating unit itself.

2. Which cavity is primarily lined by the peritoneum?

• A. Abdominal
• B. Dorsal
• C. Ventral
• D. Thoracic

Correct answer: A

Rationale: The correct answer is 'Abdominal.' The peritoneum primarily lines the abdominal cavity, providing support and protection to abdominal organs. It is a serous membrane that covers the abdominal organs and the abdominal wall, aiding in their function and protection. Choice B, 'Dorsal,' is incorrect because the peritoneum does not primarily line the dorsal cavity. Choice C, 'Ventral,' is incorrect as the peritoneum is not primarily associated with the ventral cavity. Choice D, 'Thoracic,' is incorrect because the peritoneum primarily lines the abdominal cavity and is not primarily found in the thoracic cavity.

3. In the context of optical fibers, chromatic dispersion refers to:

• A. The total internal reflection of light
• B. The spreading of light pulses due to different colors traveling at slightly different speeds
• C. The bending of light at the fiber core-cladding interface
• D. The absorption of light by the fiber material

Correct answer: B

Rationale: Chromatic dispersion in optical fibers refers to the spreading of light pulses due to different colors (wavelengths) traveling at slightly different speeds. This phenomenon can cause the different components of a light pulse to arrive at the receiver at slightly different times, leading to signal distortion. Choice A is incorrect because total internal reflection refers to the phenomenon where light is reflected back into the medium it originated from when hitting the boundary at an angle greater than the critical angle. Choice C is incorrect as it describes the principle of light being guided within an optical fiber through total internal reflection at the core-cladding interface. Choice D is incorrect as the absorption of light by the fiber material does not relate to chromatic dispersion.

4. What is the first number in a blood pressure reading?

• A. Diastolic pressure
• B. Mean arterial pressure
• C. Pulse rate
• D. Systolic pressure

Correct answer: D

Rationale: The correct answer is D: Systolic pressure. In a blood pressure reading, the first number represents the systolic pressure, which is the maximum pressure in the arteries during heart contraction. The second number in the reading is the diastolic pressure, which indicates the pressure in the arteries when the heart is at rest. Choices A, B, and C are incorrect because diastolic pressure, mean arterial pressure, and pulse rate are not the first numbers in a blood pressure reading.

5. What two factors enable some intercellular chemical signals to diffuse across cell membranes and bind to intracellular receptors?

• A. They are small and soluble.
• B. They are large and soluble.
• C. They are small and insoluble.
• D. They are large and insoluble.

Correct answer: A

Rationale: The correct answer is A: 'They are small and soluble.' Small and soluble molecules can easily pass through cell membranes and bind to intracellular receptors. Being small allows them to pass through the membrane, while being soluble enables them to dissolve in the aqueous environment inside the cell. Choice B is incorrect because large molecules typically cannot pass through the cell membrane easily. Choices C and D are incorrect because insoluble molecules would not dissolve in the aqueous environment inside the cell, hindering their ability to bind to intracellular receptors.

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