ATI RN
ATI Anatomy and Physiology Online Practice
1. Is the parietal pericardium attached to the surface of the heart?
- A. TRUE
- B. FALSE
- C. Not Sure
- D. None of the above
Correct answer: A
Rationale: The parietal pericardium is a tough, fibrous outer layer that is attached to the diaphragm and the sternum but not directly to the surface of the heart. It forms a sac around the heart known as the pericardial sac. Therefore, the statement that the parietal pericardium is attached to the surface of the heart is false.
2. In a normally functioning cardiovascular system, where does the heartbeat originate?
- A. Atrioventricular nodes
- B. Bundle of His
- C. Purkinje fibers
- D. Sinoatrial node
Correct answer: D
Rationale: The correct answer is the Sinoatrial (SA) node. The SA node is known as the natural pacemaker of the heart as it initiates the electrical impulses responsible for the heartbeat. The other choices, such as the Atrioventricular (AV) nodes, Bundle of His, and Purkinje fibers, are involved in conducting the electrical signals generated by the SA node to coordinate the heart's contractions. Therefore, they do not serve as the primary origin of the heartbeat.
3. Positive feedback mechanisms usually result in
- A. changes returning values away from a set point.
- B. stable conditions around a set point.
- C. unstable conditions.
- D. long-term changes.
Correct answer: C
Rationale: Positive feedback mechanisms usually result in unstable conditions. In a positive feedback loop, the output enhances or amplifies the changes that are occurring, leading to a deviation from the initial set point. Therefore, positive feedback does not bring values back towards the set point (Choice A). Choice B is incorrect because positive feedback does not promote stability around a set point. Choice D is also incorrect as positive feedback mechanisms typically do not lead to long-term changes; instead, they intensify the initial change, causing instability.
4. Which of the following is not an example of a homeostatic mechanism in the human body?
- A. Shivering when the body temperature falls below normal.
- B. Increasing heart rate and force of contraction when blood pressure falls.
- C. Retaining fluid excessively.
- D. Secreting insulin after a meal to return blood sugar concentration toward normal.
Correct answer: C
Rationale: The correct answer is C. Homeostatic mechanisms aim to maintain internal stability within the body. Choices A, B, and D all represent examples of homeostatic mechanisms. Shivering helps generate heat to raise body temperature back to normal levels. Increasing heart rate and force of contraction work to restore blood pressure. Insulin secretion after a meal helps regulate blood sugar levels. On the other hand, retaining fluid excessively can lead to fluid imbalance rather than maintaining internal stability, making it the incorrect choice.
5. Is cadaver dissection against the law in the U.S.?
- A. TRUE
- B. FALSE
- C. Not Sure
- D. None of the above
Correct answer: B
Rationale: Cadaver dissection is not against the law in the U.S. In fact, cadaver dissection is a common practice in medical schools and research institutions for educational and research purposes. The correct answer is 'False' because there are specific regulations and ethical guidelines that govern the use of cadavers for dissection. Choice C, 'Not Sure,' is incorrect as the legality of cadaver dissection is a well-established fact. Choice D, 'None of the above,' is also incorrect as one of the provided options is indeed correct.
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