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ATI Anatomy and Physiology Online Practice
1. Is a cell the basic unit of structure and function of an organism?
- A. True
- B. False
- C. Not Sure
- D. None of the above
Correct answer: A
Rationale: The correct answer is A: True. A cell is indeed the basic unit of structure and function of an organism. Cells are the smallest independently functioning unit in the structure of an organism and carry out vital functions necessary for life. Choice B, False, is incorrect because cells are universally recognized as the fundamental unit of life. Choice C, Not Sure, is incorrect as the role of a cell as the basic unit of an organism's structure and function is a well-established scientific fact. Choice D, None of the above, is incorrect as the statement provided in the question is true.
2. Which of the following best describes a blood clot stimulating further clotting?
- A. a positive feedback mechanism.
- B. a negative feedback mechanism.
- C. a process turning itself off.
- D. nervous system communication
Correct answer: a positive feedback mechanism.
Rationale: A blood clot stimulating further clotting is an example of a positive feedback mechanism. In positive feedback, the response enhances or amplifies the original stimulus, leading to an increase in the activity. In this case, the formation of a blood clot triggers more clotting activity, creating a cycle of increasing clot formation. Negative feedback mechanisms, on the other hand, work to maintain homeostasis by counteracting changes. Choices B, C, and D are incorrect as they do not accurately describe the situation of a blood clot stimulating further clotting.
3. Which of the following substances is involved in the destruction of ingested pathogens?
- A. lymphatic fluid
- B. stomach acid
- C. bicarbonate
- D. lipase
Correct answer: stomach acid
Rationale: The correct answer is stomach acid. Stomach acid, also known as gastric acid, plays a crucial role in destroying ingested pathogens due to its high acidity. The low pH of stomach acid helps to kill bacteria and other pathogens that may be present in the food we consume. Lymphatic fluid is involved in immune function and fat absorption, not pathogen destruction. Bicarbonate is a base that neutralizes stomach acid to prevent damage to the stomach lining. Lipase is an enzyme that aids in the digestion of fats but is not involved in pathogen destruction.
4. Which of the following is a result of stimulation of the sympathetic nervous system?
- A. decreased blood flow to the skeletal muscles
- B. increased cardiac output
- C. decreased respiratory rate
- D. increased urinary output
Correct answer: increased cardiac output
Rationale: Stimulation of the sympathetic nervous system leads to an increase in cardiac output. When the sympathetic nervous system is activated, it causes the heart to beat faster and with more force, leading to an increased cardiac output. Choices A, C, and D are incorrect because the sympathetic nervous system does not cause decreased blood flow to the skeletal muscles, decreased respiratory rate, or increased urinary output.
5. A parietal layer of a serous membrane lines cavities, whereas a visceral layer of a serous membrane covers organs.
- A. covers organs; lines cavities
- B. lines cavities; covers organs
- C. secretes serous fluid; secretes mucus
- D. secretes mucus; secretes a serous fluid
Correct answer: lines cavities; covers organs
Rationale: In serous membranes, the parietal layer lines the cavities, providing support and protection, while the visceral layer covers the organs, reducing friction and allowing them to move freely. Therefore, the correct answer is 'lines cavities; covers organs.' Choices C and D are incorrect because serous membranes do not secrete mucus; instead, they secrete a watery serous fluid. Choice A is incorrect as it reverses the functions of the parietal and visceral layers in relation to organs and cavities.
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