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. What function is associated with the dermal layer of the skin?

A. Sensory perception
B. To provide support and structure to the skin
C. Protection from UV rays
D. Insulation

Correct answer: B

Rationale: The correct function associated with the dermal layer of the skin is to provide support and structure to the skin. The dermis is the thickest layer of the skin and is responsible for maintaining the skin's integrity and firmness. Choices A, C, and D are incorrect as sensory perception, protection from UV rays, and insulation are functions associated with other layers of the skin, such as the epidermis and subcutaneous tissue.

3. Which of the following is not true of organelles?

A. They carry out specific activities.
B. They are only present in human cells.
C. They are composed of aggregates of large molecules.
D. They are found in many types of cells.

Correct answer: B

Rationale: Organelles are not exclusive to human cells but are present in various types of cells across different organisms. Option B is incorrect as it suggests that organelles are only found in human cells, which is false. Choices A, C, and D are correct statements about organelles. Organelles indeed carry out specific activities, are made up of aggregates of large molecules, and can be found in many types of cells.

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

A. Maintaining blood pressure
B. Uterine contractions during childbirth
C. Body temperature control
D. Control of blood sugar

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.

5. 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.