Nursing Elites

1. Which white blood cell type is responsible for the initial attack on pathogens?

• A. Red blood cells
• B. Platelets
• C. Phagocytes
• D. Lymphocytes

Correct answer: C

Rationale: Phagocytes are a type of white blood cell that is crucial in the initial attack on pathogens. These cells have the ability to engulf and digest foreign particles such as bacteria and viruses, thereby preventing infections. Red blood cells primarily function in oxygen transport, platelets are vital for blood clotting, and lymphocytes are involved in the immune response. However, phagocytes are specifically designed to provide the initial defense against pathogens by directly attacking and eliminating them.

2. What property of a substance remains constant regardless of changes in gravity?

• A. Mass
• B. Weight
• C. Volume
• D. Density

Correct answer: A

Rationale: Mass is a measure of the amount of matter in an object and remains constant regardless of changes in gravity. Weight, on the other hand, is a measure of the gravitational force acting on an object and varies with changes in gravity. Volume is the amount of space occupied by an object and can change with changes in gravity. Density is the mass of a substance per unit volume and can also change with changes in gravity if the volume changes. Therefore, the correct answer is mass as it remains the same regardless of the gravitational force acting on the object, making it an intrinsic property of the substance.

3. Which type of joint allows for rotational movement around a single axis?

• A. Ball-and-socket joint
• B. Pivot joint
• C. Hinge joint
• D. Saddle joint

Correct answer: B

Rationale: The correct answer is a Pivot joint. A pivot joint, like the joint in the neck, enables rotational movement around a single axis. This type of joint is crucial for allowing the head to turn from side to side. Choice A, Ball-and-socket joint, allows for movement in multiple axes due to its spherical structure, not limited to single-axis rotation. Choice C, Hinge joint, allows movement in one plane like a door hinge, but not rotational movement around a single axis. Choice D, Saddle joint, allows movement in multiple directions but is not specifically designed for rotational movement around a single axis.

4. What describes the change in direction of light when it passes through different mediums, such as air and water?

• A. Diffraction
• B. Reflection
• C. Refraction
• D. Dispersion

Correct answer: C

Rationale: Refraction is the change in direction of light as it moves from one medium to another, such as air to water or glass. This change occurs due to variations in the speed of light in each medium, causing the light rays to bend. When light passes through different mediums, it changes its path, a phenomenon known as refraction. Choice A, Diffraction, refers to the bending of waves around obstacles and the spreading of waves when passing through small openings, not the change in direction of light when moving between mediums. Choice B, Reflection, is the bouncing back of light rays from a surface into the same medium, not the change in direction when transitioning between different mediums. Choice D, Dispersion, involves the separation of light into its constituent colors based on their different wavelengths, not the change in direction of light when passing through different mediums.

5. What is the primary function of tight junctions, specialized regions between animal cells?

• A. Communication between cells
• B. Anchorage between cells
• C. Selective passage of materials
• D. All of the above

Correct answer: C

Rationale: The correct answer is C: Selective passage of materials. Tight junctions act as specialized structures between animal cells that create a barrier to the passage of materials. Their primary function is to prevent the leakage of extracellular fluid and control the selective passage of molecules between cells. This selective control is crucial in regulating the movement of substances across cell layers. Tight junctions do not directly facilitate communication between cells or provide anchorage between cells, as their main role is to regulate the passage of materials. Choices A and B are incorrect as tight junctions do not primarily serve for communication or anchorage between cells.

Similar Questions