Nursing Elites

1. After exposure to a pathogen, the immune system develops memory. What type of immune cell is responsible for this immunological memory?

• A. B cells
• B. T cells (specifically memory T cells)
• C. Phagocytes
• D. Natural killer cells

Correct answer: A

Rationale: B cells are responsible for immunological memory. Memory B cells, a type of B cells, retain a 'memory' of specific pathogens, enabling them to rapidly produce antibodies upon re-exposure. This rapid antibody production facilitates a quicker and more effective immune response. Although memory T cells also contribute to immunological memory by mounting a swift and robust immune response upon re-exposure to the pathogen, it is primarily memory B cells that play a crucial role in producing antibodies. Phagocytes are important immune cells involved in engulfing and digesting pathogens, while natural killer cells are primarily responsible for recognizing and eliminating abnormal cells, such as virus-infected cells or tumor cells. However, when it comes to immunological memory and antibody production, B cells are key players.

2. Which state of matter has a definite shape and volume but can flow?

• A. Solid
• B. Liquid
• C. Gas
• D. Plasma

Correct answer: B

Rationale: A liquid is the state of matter that has a definite volume but can flow and take the shape of its container. Solids have a definite shape and volume but do not flow as liquids do. Gases do not have a definite shape or volume but can flow to fill their container. Plasma is a state of matter where the particles are highly energized and do not have a definite shape or volume, thus not fitting the description of having a definite shape and volume while being able to flow.

3. Which of the following is responsible for transporting oxygen in the blood?

• A. White blood cells
• B. Red blood cells
• C. Platelets
• D. Plasma

Correct answer: B

Rationale: Red blood cells are responsible for transporting oxygen in the blood. Hemoglobin, a protein found in red blood cells, binds to oxygen in the lungs and carries it to tissues throughout the body. White blood cells are involved in the immune system's defense mechanisms against infections, platelets help in blood clotting, and plasma is the liquid component of blood that carries various substances like nutrients, hormones, and waste products.

4. 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.

5. Which nervous system controls the involuntary 'fight-or-flight' response?

• A. Sympathetic nervous system
• B. Parasympathetic nervous system
• C. Enteric nervous system
• D. Sensory nervous system

Correct answer: A

Rationale: The correct answer is the sympathetic nervous system. The sympathetic nervous system is responsible for activating the body's response to stress or danger, leading to the 'fight-or-flight' response. It prepares the body for action by increasing heart rate, dilating pupils, and redirecting blood flow to muscles. Choice B, the parasympathetic nervous system, is responsible for the body's 'rest-and-digest' activities, which are opposite to the 'fight-or-flight' response. Choice C, the enteric nervous system, primarily regulates the gastrointestinal system and is not directly involved in the 'fight-or-flight' response. Choice D, the sensory nervous system, transmits sensory information from the body to the central nervous system and is not responsible for the physiological changes associated with the 'fight-or-flight' response.

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