which of the following illustrates a positive feedback mechanism
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Nursing Elites

ATI RN

ATI Anatomy and Physiology Online Practice

1. Which of the following illustrates a positive feedback mechanism?

Correct answer: B

Rationale: The correct answer is uterine contractions during childbirth. This is an example of a positive feedback mechanism where the initial stimulus (contractions) leads to an increase in intensity and frequency, ultimately resulting in childbirth. In contrast, choices A, C, and D (maintaining blood pressure, body temperature control, and control of blood sugar) are examples of negative feedback mechanisms. These mechanisms work to maintain stability by counteracting any deviations from the set point, rather than amplifying the response like in a positive feedback mechanism.

2. In negative feedback mechanisms, changes away from the normal state

Correct answer: C

Rationale: In negative feedback mechanisms, changes away from the normal state stimulate changes in the opposite direction. This is a fundamental concept in biological systems where the response to a stimulus opposes the initial change, helping to maintain homeostasis. Choice A is incorrect because negative feedback does not stimulate changes in the same direction. Choice B is incorrect because negative feedback does not inhibit all body reactions, but rather specific responses. Choice D is incorrect because negative feedback does not stimulate a reduction in all body requirements, but rather adjusts specific functions to restore balance.

3. Are kidneys part of the lymphatic system?

Correct answer: B

Rationale: The correct answer is False. Kidneys are not part of the lymphatic system; they are part of the urinary system. The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials. Therefore, choices A, C, and D are incorrect because kidneys are not associated with the lymphatic system.

4. An obstetrician tells a 42-year-old patient that she can have a healthy baby, but that she is of 'advanced maternal age.' The patient is so upset that she fails to listen to the rest of the doctor's advice, goes home in a huff, and immediately dyes her hair.

Correct answer: B

Rationale: The correct answer is 'the age of her eggs.' As women age, the quality of their eggs decreases, leading to a higher risk of chromosomal abnormalities and infertility. This decline in egg quality is why advanced maternal age is associated with a higher risk of certain pregnancy complications. Choices A, C, and D are incorrect because the primary concern in this context is related to the age-related changes in a woman's eggs, not sperm, diabetes risk, or cholesterol levels.

5. What causes wrinkled and sagging skin?

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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