Nursing Elites

1. Homologous structures are those that:

• A. Have the same function but different origins
• B. Have different functions but the same origin
• C. Are similar in appearance and function due to shared ancestry
• D. Are identical in both appearance and function

Correct answer: C

Rationale: Homologous structures are defined as anatomical features that are similar in appearance and function due to shared ancestry. This means that these structures are inherited from a common ancestor and may have evolved to fulfill different functions in different species. Option A, which mentions structures with the same function but different origins, describes analogous structures, not homologous ones. Option B, which refers to structures with different functions but the same origin, actually characterizes vestigial structures. Option D, stating that structures are identical in appearance and function, does not necessarily imply homology; such structures could result from convergent evolution rather than shared ancestry. Understanding homologous structures provides insights into the evolutionary relationships between different species and supports the concept of common descent.

2. What is the name of the master gland that regulates the function of many other endocrine glands?

• A. Thyroid gland
• B. Pituitary gland
• C. Hypothalamus
• D. Adrenal gland

Correct answer: B

Rationale: The pituitary gland is commonly referred to as the master gland because it controls the functions of numerous other endocrine glands in the body. It secretes various hormones that are essential for regulating processes like growth, metabolism, reproduction, and stress response. The thyroid gland (Choice A) primarily regulates metabolism and does not oversee other endocrine glands. The hypothalamus (Choice C) plays a role in regulating the pituitary gland but is not the master gland. The adrenal gland (Choice D) produces hormones related to stress response but is not considered the master gland that regulates other endocrine glands.

3. Which organ system is most responsible for maintaining control of body temperature?

• A. The skeletal system.
• B. The circulatory system.
• C. The immune system.
• D. The muscular system.

Correct answer: B

Rationale: The circulatory system is the correct answer as it plays a crucial role in maintaining control of body temperature through a process called thermoregulation. Blood vessels near the skin surface dilate to dissipate heat when the body is too warm and constrict to reduce heat loss when it's too cold. Additionally, the circulatory system helps distribute heat produced from metabolic processes throughout the body to keep a stable internal temperature. The skeletal system provides structural support, the immune system defends against pathogens, and the muscular system is responsible for movement, but they are not primarily involved in regulating body temperature.

4. How do isotopes affect the atomic mass of an element?

• A. Isotopes have no effect on the atomic mass of an element.
• B. Isotopes cause the atomic mass of an element to vary slightly.
• C. Isotopes cause the atomic mass of an element to be exactly the same for all isotopes of that element.
• D. Isotopes cause the atomic mass of an element to vary greatly.

Correct answer: B

Rationale: Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons. Since the atomic mass of an element is the weighted average of the masses of its isotopes, the presence of isotopes causes the atomic mass of an element to vary slightly. This variation occurs because different isotopes have different masses due to their varying numbers of neutrons. The atomic mass is affected by the abundance of each isotope, leading to a slight fluctuation in the overall atomic mass of the element. Choice A is incorrect because isotopes do influence the atomic mass. Choice C is incorrect because isotopes have different masses, affecting the overall atomic mass. Choice D is incorrect as isotopes typically do not cause a significant variation in atomic mass, but rather a slight fluctuation.

5. Which blood vessels transport blood from the capillaries back to the heart?

• A. Arterioles
• B. Veins
• C. Venules
• D. Capillaries

Correct answer: B

Rationale: Veins are the correct answer as they are the blood vessels that carry blood from the capillaries back to the heart. Veins have thinner walls compared to arteries and contain valves to prevent blood from flowing backward. This transport of blood from the capillaries to the heart is essential for the circulatory system to maintain proper blood flow and oxygenation levels. Arterioles are small branches of arteries that lead to capillaries, not vessels that transport blood back to the heart. Venules are small vessels that collect blood from capillaries and lead to veins. Capillaries are the smallest blood vessels where the exchange of gases and nutrients occurs between blood and tissues, not vessels that transport blood back to the heart.

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