homeostasis is the

ATI RN

ATI Anatomy and Physiology Online Practice

1. What is homeostasis?

A. The inability to keep body weight within normal limits.
B. Room temperature decreasing because a window is open.
C. Ingestion of more food than needed.
D. The tendency of the body to maintain a stable internal environment.

Correct answer: D

Rationale: The correct answer is D: Homeostasis refers to the body's ability to maintain a stable internal environment despite external changes. Choices A, B, and C are incorrect. Choice A describes obesity, choice B describes a specific scenario with room temperature, and choice C refers to overeating, which is not related to homeostasis.

2. Which of the following characteristics of life and their descriptions are correct?

A. Responsiveness - detecting and responding to changes in the environment
B. Assimilation - incorporating absorbed substances into the body
C. Respiration - obtaining energy from food molecules through oxygen
D. Circulation - the movement of substances in body fluids

Correct answer: D

Rationale: The correct answer is D: Circulation - the movement of substances in body fluids. Circulation refers to the movement of substances like nutrients, gases, and wastes in body fluids to and from cells. Choice A is incorrect because responsiveness is about detecting and responding to changes in the environment, not obtaining and using oxygen. Choice B is incorrect because assimilation is the process of incorporating absorbed substances into the body, not changing them into chemically different forms. Choice C is incorrect because respiration is the process of obtaining energy from food molecules through oxygen, not the obtaining and using oxygen itself.

3. Which part of the brain regulates heart rate, respiratory rate, and blood pressure?

A. Corpus Callosum
B. Medulla Oblongata
C. Pituitary Glands
D. Pineal Glands

Correct answer: B

Rationale: The correct answer is the Medulla Oblongata. This part of the brain is responsible for regulating essential autonomic functions such as heart rate, respiratory rate, and blood pressure. The Corpus Callosum is responsible for connecting the left and right hemispheres of the brain, not for regulating these vital functions. The Pituitary Glands and Pineal Glands are part of the endocrine system and are not directly involved in regulating heart rate, respiratory rate, and blood pressure.

4. What do positive feedback mechanisms do?

A. Cause long-term changes.
B. Move conditions away from the normal state.
C. Bring conditions back to the normal state.
D. Usually produce stable conditions.

Correct answer: B

Rationale: Positive feedback mechanisms amplify or increase changes in a system, moving conditions away from the normal state. This makes choice B the correct answer. Choice A is incorrect as positive feedback does not cause long-term changes but rather accelerates deviations from the norm. Choice C is incorrect because positive feedback does not bring conditions back to normal; instead, it amplifies deviations. Choice D is incorrect as positive feedback does not usually lead to stable conditions but rather to further deviations from the normal state.

5. Metabolism is defined as _____.

A. the removal of wastes produced by chemical reactions
B. the breakdown of substances into simpler forms
C. the taking in of nutrients
D. all the chemical reactions occurring in an organism that support life

Correct answer: D

Rationale: Metabolism refers to all the chemical reactions that take place within an organism to sustain life, including processes such as breaking down molecules, building new molecules, and energy production. Choice A is incorrect because it describes excretion rather than metabolism. Choice B is incorrect as it specifically refers to the breakdown of substances, not encompassing the entirety of metabolic processes. Choice C is incorrect as it focuses solely on nutrient intake, which is just one aspect of metabolism.