Nursing Elites

1. When animals eat, insulin is released from the pancreas, stimulating glucose uptake by the liver. When glucose levels drop, the pancreas reduces insulin release. This is an example of which mechanism for maintaining homeostasis?

• A. Negative feedback.
• B. Positive feedback.
• C. Stress response.
• D. Parasympathetic regulation.

Correct answer: A

Rationale: This mechanism is an example of negative feedback. Negative feedback systems work to counteract changes in the body and maintain a stable internal environment (homeostasis). In this case, the release of insulin in response to high glucose levels is followed by a reduction in insulin release when glucose levels drop. This response helps regulate glucose levels and return them to a normal range, demonstrating the characteristic of negative feedback where the body's response opposes the initial stimulus to maintain equilibrium. Positive feedback would amplify the initial change rather than counteract it, so it is not the correct choice. Stress response and parasympathetic regulation are not directly involved in this glucose regulation process, making them incorrect choices.

2. What element is responsible for the red color of blood?

• A. Magnesium
• B. Iron
• C. Copper
• D. Zinc

Correct answer: B

Rationale: The correct answer is B: Iron. Hemoglobin, the protein responsible for carrying oxygen in red blood cells, contains iron in its heme group, contributing to the blood's characteristic red color. Magnesium (choice A), copper (choice C), and zinc (choice D) are not responsible for the red color of blood. Magnesium is an essential mineral involved in various physiological processes, copper is a trace element important for enzyme function, and zinc is a micronutrient essential for multiple cellular functions but not related to the red color of blood.

3. Passive transport does not require energy input from the cell. Which of the following is an example of passive transport?

• A. Active transport of ions across a membrane
• B. Diffusion of small molecules across a concentration gradient
• C. Movement of large molecules using vesicles
• D. Endocytosis of particles into the cell

Correct answer: B

Rationale: Passive transport refers to the movement of molecules across a cell membrane without the input of energy. Diffusion of small molecules across a concentration gradient is a classic example of passive transport, as it occurs spontaneously from an area of high concentration to an area of low concentration. Active transport (option A) requires energy input in the form of ATP to move substances against their concentration gradient. Movement of large molecules using vesicles (option C) involves processes like endocytosis and exocytosis that require energy in the form of ATP. Endocytosis of particles into the cell (option D) is an active process that requires energy expenditure by the cell to engulf and internalize extracellular substances.

4. Which structure in the lungs is the site of gas exchange?

• A. Trachea
• B. Alveoli
• C. Bronchioles
• D. Diaphragm

Correct answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from inhaled air diffuses into the bloodstream, while carbon dioxide from the blood is released into the alveoli to be exhaled. The trachea (Choice A) is the windpipe that carries air to and from the lungs, but it is not involved in gas exchange. Bronchioles (Choice C) are small air passages within the lungs that branch off from the bronchi, leading air to the alveoli but not directly involved in gas exchange. The diaphragm (Choice D) is a muscle below the lungs that helps in breathing by expanding and contracting the chest cavity, but it is not the site of gas exchange.

5. What are the white blood cells responsible for coordinating the immune response called?

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

Correct answer: C

Rationale: Lymphocytes, which include B cells, T cells, and natural killer cells, are responsible for coordinating the immune response. They play a crucial role in recognizing and fighting against pathogens and foreign substances in the body. Red blood cells are responsible for oxygen transport, platelets aid in blood clotting, and neutrophils are white blood cells primarily involved in combating infections. Therefore, the correct answer is C, lymphocytes, as they are specifically involved in coordinating immune responses.

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