Nursing Elites

1. Maintaining a stable internal environment typically requires

• A. positive feedback mechanisms.
• B. an unstable outside environment.
• C. decreased atmospheric pressure.
• D. negative feedback mechanisms.

Correct answer: D

Rationale: The correct answer is 'negative feedback mechanisms.' In biological systems, negative feedback mechanisms help maintain homeostasis by counteracting any deviations from the set point. They work to stabilize internal conditions and keep them within a narrow range. On the other hand, positive feedback mechanisms amplify changes and are not involved in maintaining stability. Choice B, 'an unstable outside environment,' is incorrect as internal stability is independent of external conditions like weather. Choice C, 'decreased atmospheric pressure,' is also incorrect as it does not directly relate to internal homeostasis.

2. Which of the following structures of the gastrointestinal system absorbs iron and bile salts?

• A. Ileum
• B. Jejunum
• C. Colon
• D. Duodenum

Correct answer: A

Rationale: The correct answer is the Ileum. The Ileum is the final section of the small intestine where the absorption of key nutrients such as iron and bile salts occurs. The Jejunum mainly absorbs nutrients like carbohydrates and proteins, while the Duodenum primarily facilitates the absorption of minerals and vitamins. The Colon's main function is to absorb water and electrolytes, not iron and bile salts. Therefore, choices B, C, and D are incorrect.

3. Cells do not aggregate into organelles based on similar functions.

• A. TRUE
• B. FALSE
• C. Not Sure
• D. None of the above

Correct answer: B

Rationale: The statement is false. Cells with similar functions do not aggregate into organelles. Organelles are specialized structures within cells that perform specific functions, such as the nucleus, mitochondria, and endoplasmic reticulum. Cells themselves are the basic structural and functional units of organisms, and organelles are located within cells to carry out various tasks. Therefore, cells do not aggregate into organelles, but organelles are found within cells to support their functions. Choices A, C, and D are incorrect as cells do not form organelles by aggregating based on similar functions.

4. Which of the following illustrates a positive feedback mechanism?

• A. Maintaining blood pressure
• B. Uterine contractions during childbirth
• C. Body temperature control
• D. Control of blood sugar

Correct answer: B

Rationale: The correct answer is uterine contractions during childbirth. This is an example of a positive feedback mechanism where the initial stimulus (contractions) leads to an increase in intensity and frequency, ultimately resulting in childbirth. In contrast, choices A, C, and D (maintaining blood pressure, body temperature control, and control of blood sugar) are examples of negative feedback mechanisms. These mechanisms work to maintain stability by counteracting any deviations from the set point, rather than amplifying the response like in a positive feedback mechanism.

5. The ability of an organism to sense and react to changes in its body illustrates

• A. circulation.
• B. respiration.
• C. responsiveness.
• D. absorption

Correct answer: C.

Rationale: The correct answer is 'responsiveness.' Responsiveness refers to the ability of an organism to detect and respond to stimuli in its environment. In this context, it specifically relates to an organism's ability to sense and react to changes within its body. Choices A, B, and D are incorrect. Circulation refers to the movement of fluids within an organism, respiration is the process of exchanging gases, and absorption is the uptake of substances by cells or tissues.

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