ATI RN
ATI Anatomy and Physiology Online Practice
1. Homeostasis exists if concentrations of water, nutrients, and oxygen in the body and heat and pressure __________.
- A. decrease steadily
- B. remain within certain limited ranges
- C. increase when the body is stressed
- D. fluctuate greatly between very high and low values
Correct answer: B
Rationale: Homeostasis is the body's ability to maintain stable internal conditions despite external changes. To achieve this balance, concentrations of essential substances must remain within specific ranges. Choice A is incorrect because decreasing concentrations would not maintain stability. Choice C is incorrect as increasing concentrations when the body is stressed would disrupt homeostasis. Choice D is incorrect as fluctuating greatly between high and low values would also not support the body's stability. Therefore, the correct answer is B, as it aligns with the concept of homeostasis by emphasizing the need for stability within certain limits.
2. Which of the following electrolytes plays an essential role in the clotting of blood?
- A. sodium
- B. magnesium
- C. calcium
- D. potassium
Correct answer: C
Rationale: Calcium plays an essential role in the clotting of blood by being involved in several steps of the coagulation process. It is necessary for the conversion of prothrombin to thrombin, which is a crucial step in forming blood clots. Sodium, magnesium, and potassium do not directly participate in the clotting cascade and are not associated with the coagulation process. Therefore, the correct answer is calcium.
3. Ceroid pigments and lipofuscin accumulate with aging, impairing a cell's ability to withstand the damaging effects of oxygen free radicals.
- A. TRUE
- B. FALSE
- C. Not Sure
- D. None of the above
Correct answer: A
Rationale: The statement provided in the question is true. Ceroid pigments and lipofuscin are products of cellular damage and aging. These substances accumulate within cells over time and can impair cellular functions, including the ability to withstand the damaging effects of oxygen free radicals. Choice B, 'False,' is incorrect because the accumulation of ceroid pigments and lipofuscin does indeed impair a cell's ability to deal with oxidative stress. Choices C and D are also incorrect as the statement is true.
4. Homeostasis is the body's maintenance of a stable internal environment.
- A. TRUE
- B. FALSE
- C. Not Sure
- D. None of the above
Correct answer: A
Rationale: Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. It involves processes that regulate various physiological factors such as temperature, pH, and blood sugar levels within a narrow range. This ensures that the body's cells can function optimally. Therefore, the correct answer is True. Choices B, C, and D are incorrect because homeostasis aims to maintain stability, not instability, in the internal environment.
5. What causes wrinkled and sagging skin?
- A. Drinking too much water
- B. Heredity alone
- C. Loss of subcutaneous fat and reduced levels of elastin and collagen
- D. Excess subcutaneous fat
Correct answer: C
Rationale: Wrinkled and sagging skin is primarily caused by the loss of subcutaneous fat and reduced levels of elastin and collagen in the skin. Choice A is incorrect as drinking too much water does not lead to wrinkled and sagging skin. Choice B is incorrect because heredity alone does not cause this condition. Excess subcutaneous fat, as mentioned in Choice D, can contribute to a different skin appearance, such as puffiness, but not wrinkled and sagging skin.
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