which of the following ions is most abundant in extracellular fluid

ATI RN

ATI Anatomy and Physiology

1. Which of the following ions is most abundant in extracellular fluid?

A. Calcium
B. Chloride
C. Sodium
D. Potassium

Correct answer: C

Rationale: Sodium is the most abundant ion in extracellular fluid. It plays a crucial role in maintaining fluid balance, nerve function, and muscle contraction. Calcium (Choice A) is mainly found in bones and teeth, Chloride (Choice B) is the major anion in extracellular fluid but not the most abundant ion, and Potassium (Choice D) is found predominantly inside cells.

2. 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.

3. What does magnetic resonance imaging use?

A. X-rays.
B. a radio antenna.
C. radioisotopes.
D. high-frequency sound waves.

Correct answer: D

Rationale: Magnetic resonance imaging (MRI) uses high-frequency sound waves to create detailed images of the inside of the body. X-rays (Choice A) use electromagnetic radiation, not sound waves, making it an incorrect choice. A radio antenna (Choice B) is used for communication, not for MRI imaging. Radioisotopes (Choice C) are used in nuclear medicine imaging techniques, not in MRI scans. Therefore, the correct answer is high-frequency sound waves (Choice D) as they are utilized in MRI technology to produce images.

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. Which of the following best describes a blood clot stimulating further clotting?

A. a positive feedback mechanism.
B. a negative feedback mechanism.
C. a process turning itself off.
D. nervous system communication

Correct answer: A

Rationale: A blood clot stimulating further clotting is an example of a positive feedback mechanism. In positive feedback, the response enhances or amplifies the original stimulus, leading to an increase in the activity. In this case, the formation of a blood clot triggers more clotting activity, creating a cycle of increasing clot formation. Negative feedback mechanisms, on the other hand, work to maintain homeostasis by counteracting changes. Choices B, C, and D are incorrect as they do not accurately describe the situation of a blood clot stimulating further clotting.