Nokea
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.
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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.
Which of the following must the human body obtain from the environment in order to survive?
- A. Nitrogen
- B. Waste products
- C. Water
- D. Carbon dioxide
Correct Answer: C
Rationale: The correct answer is C: Water. Water is essential for the human body to survive as it plays a crucial role in various physiological processes like digestion, circulation, and temperature regulation. Nitrogen is abundant in the atmosphere and is not directly obtained from the environment for survival. Waste products are materials that need to be eliminated from the body, not obtained for sustenance. Carbon dioxide is a byproduct of cellular respiration and is expelled from the body through breathing, not obtained as a nutrient.
Signs of aging at the cellular level are
- A. graying hair, waning strength, and wrinkles.
- B. unrepaired DNA and abnormal proteins.
- C. impaired cell division and the ability to break down and recycle worn cell parts.
- D. a fatty liver and clogged blood vessels.
Correct Answer: C
Rationale: The correct answer is 'impaired cell division and the ability to break down and recycle worn cell parts.' Aging at the cellular level involves reduced efficiency in cell division and the breakdown/recycling of cellular components, leading to functional decline. Choices A, B, and D are incorrect because they involve external physical manifestations or organ-specific issues rather than cellular-level changes associated with aging.
Why are anatomy and physiology difficult to separate?
- A. Physiological functions depend on anatomical structures.
- B. Physiological functions in an organism are ongoing.
- C. Body parts provide structural support.
- D. Our understanding of physiology is changing more than our understanding of anatomy.
Correct Answer: A
Rationale: Anatomy and physiology are difficult to separate because physiological functions depend on anatomical structures. The correct answer highlights the interdependence between the two disciplines; physiological functions are carried out by anatomical structures. Choice B is incorrect as it only states a characteristic of physiological functions without addressing the relationship with anatomy. Choice C is incorrect as it talks about body parts providing structural support, which is not directly related to the interdependence of anatomy and physiology. Choice D is incorrect because the rate of change in understanding does not necessarily dictate the difficulty of separating the two disciplines.
The removal of wastes produced by metabolic reactions is
- A. metabolism.
- B. absorption.
- C. assimilation.
- D. excretion.
Correct Answer: D.
Rationale: The correct answer is 'excretion.' Excretion is the process of eliminating waste products produced by metabolic reactions from the body. Metabolism (Choice A) refers to the chemical processes that occur within a living organism to maintain life. Absorption (Choice B) is the process of taking in nutrients and fluids into the body. Assimilation (Choice C) is the process of absorbing and incorporating nutrients into the body after digestion. Therefore, excretion is the most appropriate term for the removal of metabolic wastes.