ATI RN
ATI Anatomy and Physiology
1. Which of the following ions is most abundant in extracellular fluid?
- A. Calcium
- B. Chloride
- C. Sodium
- D. Potassium
Correct answer: C
Rationale: Sodium is the most abundant ion in extracellular fluid. It plays a crucial role in maintaining fluid balance, nerve function, and muscle contraction. Calcium (Choice A) is mainly found in bones and teeth, Chloride (Choice B) is the major anion in extracellular fluid but not the most abundant ion, and Potassium (Choice D) is found predominantly inside cells.
2. What is assimilation?
- A. changing absorbed substances into different chemical forms
- B. breaking down foods into nutrients that the body can absorb
- C. eliminating waste from the body
- D. an increase in body size without a change in overall shape
Correct answer: A
Rationale: Assimilation is the process of changing absorbed substances into different chemical forms. It occurs after nutrients from food are absorbed into the bloodstream and used by the body. Choice B, breaking down foods into nutrients that the body can absorb, refers to the process of digestion rather than assimilation. Choice C, eliminating waste from the body, describes the process of excretion. Choice D, an increase in body size without a change in overall shape, does not accurately define assimilation.
3. When does cell death first occur?
- A. At age 60.
- B. At age 50.
- C. At puberty.
- D. In the fetus.
Correct answer: D
Rationale: Cell death, also known as apoptosis, first occurs during fetal development when specific cells are programmed to die. This process is essential for shaping and organizing tissues and organs. Choices A, B, and C are incorrect because cell death begins much earlier, during fetal development, rather than later in life or at puberty. Understanding the timing of cell death in different stages of life is crucial in developmental biology.
4. 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.
5. What effect does aldosterone secretion have on electrolyte levels?
- A. Calcium levels are decreased
- B. Sodium levels are increased
- C. Potassium levels are increased
- D. Magnesium levels are decreased
Correct answer: B
Rationale: Aldosterone is a hormone that primarily acts on the kidneys to increase the reabsorption of sodium and water into the bloodstream. As a result, sodium levels are increased. Choices A, C, and D are incorrect. Aldosterone does not significantly affect calcium, potassium, or magnesium levels.
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