Nursing Elites

1. Which of the following structures is responsible for gas exchange in the lungs?

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

Correct answer: B

Rationale: The alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place. Oxygen from inhaled air diffuses into the blood vessels surrounding the alveoli, while carbon dioxide from the blood is released into the alveoli to be exhaled. The bronchi are air passages that carry air into the lungs but do not participate in gas exchange. The trachea is the windpipe that connects the larynx to the bronchi and serves as an airway for breathing. The diaphragm is a muscle that aids in the breathing process by contracting and relaxing to change the volume of the chest cavity.

2. What happens to the density of a gas when its temperature increases at constant pressure?

• A. It increases.
• B. It decreases.
• C. It remains the same.
• D. Information is insufficient.

Correct answer: B

Rationale: When the temperature of a gas increases at constant pressure, the average kinetic energy of the gas molecules increases. This leads to the gas molecules moving faster and spreading out more, which causes them to occupy a larger volume. As a result, the density of the gas decreases because the same number of gas molecules are now distributed over a larger space. Choice A is incorrect because as the gas molecules spread out, the density decreases. Choice C is incorrect because the increase in temperature leads to a decrease in density due to the increased volume occupied by the gas molecules. Choice D is incorrect because with the provided scenario of temperature increase at constant pressure, the effect on density can be determined.

3. The average life expectancy at birth in the United States at the beginning of the 21st century was about 75 years. The average life expectancy at birth in the middle of the 19th century was only about 40 years. Which of the following factors are likely to have contributed to the longer life expectancy in the 21st century? (Select the one that does not apply)

• A. The human body has evolved to become more resilient to its environment.
• B. There have been numerous advances in medical technology and treatments.
• C. Higher standards of basic cleanliness have helped people avoid illness.
• D. The creation of vaccines has nearly eliminated certain diseases that were once deadly.

Correct answer: A

Rationale: Medical advances, higher standards of cleanliness, and the creation of vaccines have all significantly contributed to the increase in life expectancy over time. While human evolution plays a role in adaptation to the environment over millennia, it is not a primary factor that has led to the substantial increase in life expectancy within a few centuries. The human body's evolution is a slow process that occurs over generations, while the advancements in medical technology, cleanliness, and vaccines have had a more immediate and direct impact on improving life expectancy.

4. Which type of cartilage allows for smooth movement at joints and absorbs shock?

• A. Hyaline cartilage
• B. Fibrocartilage
• C. Elastic cartilage
• D. None of the above

Correct answer: B

Rationale: Fibrocartilage is the correct answer. It is found in areas requiring both support and resilience, such as the intervertebral discs and knee joints. Fibrocartilage contains collagen fibers for strength and proteoglycans for resilience, making it suitable for functions that involve smooth movement at joints and shock absorption. Hyaline cartilage, while providing structural support, is not primarily responsible for smooth movement and shock absorption. Elastic cartilage is more flexible and is found in locations like the ear and epiglottis, but it is not known for its shock-absorbing properties. Choosing 'None of the above' disregards the correct option of fibrocartilage, which is specifically designed for the functions described in the question.

5. During exercise, oxygen is used to convert glucose into energy for muscles. This process is called:

• A. Aerobic respiration
• B. Anaerobic respiration
• C. Glycolysis
• D. Lactic acid fermentation

Correct answer: A

Rationale: Aerobic respiration is the process by which cells use oxygen to convert glucose into energy. This process occurs in the mitochondria of cells and is the most efficient way to produce energy during exercise. Anaerobic respiration and glycolysis are alternative pathways for energy production when oxygen is limited, typically occurring during high-intensity exercise. Lactic acid fermentation, on the other hand, occurs in the absence of oxygen and leads to the production of lactic acid, causing muscle fatigue and soreness.

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