ATI RN
ATI Anatomy and Physiology
1. In a normally functioning cardiovascular system, where does the heartbeat originate?
- A. Atrioventricular nodes
- B. Bundle of His
- C. Purkinje fibers
- D. Sinoatrial node
Correct answer: D
Rationale: The correct answer is the Sinoatrial (SA) node. The SA node is known as the natural pacemaker of the heart as it initiates the electrical impulses responsible for the heartbeat. The other choices, such as the Atrioventricular (AV) nodes, Bundle of His, and Purkinje fibers, are involved in conducting the electrical signals generated by the SA node to coordinate the heart's contractions. Therefore, they do not serve as the primary origin of the heartbeat.
2. 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.
3. When does cell death first occur?
- A. At age 60.
- B. At age 50.
- C. At puberty.
- D. In the fetus.
Correct answer: D
Rationale: Cell death, also known as apoptosis, first occurs during fetal development when specific cells are programmed to die. This process is essential for shaping and organizing tissues and organs. Choices A, B, and C are incorrect because cell death begins much earlier, during fetal development, rather than later in life or at puberty. Understanding the timing of cell death in different stages of life is crucial in developmental biology.
4. Which of the following are vital signs?
- A. Body temperature, blood pressure, and pulse rate
- B. Appearance of the skin, red blood cell count, oxygen level
- C. Body weight, age, gender
- D. Visual acuity and auditory sharpness
Correct answer: A
Rationale: The correct answer is A: Body temperature, blood pressure, and pulse rate. Vital signs are measurements that indicate the body's basic functions and are essential indicators of health. Body temperature, blood pressure, and pulse rate are classic vital signs routinely checked in medical settings to assess a person's overall health status. Choices B, C, and D are not considered vital signs. The appearance of the skin, red blood cell count, and oxygen level may provide valuable health information but are not classified as vital signs. Similarly, body weight, age, and gender are important factors in healthcare but are not vital signs. Visual acuity and auditory sharpness relate to sensory functions and are not typically categorized as vital signs.
5. Which of the following may indicate hypersecretion of thyroid hormone?
- A. weight loss
- B. Bradycardia
- C. cold intolerance
- D. lethargy
Correct answer: A
Rationale: Weight loss is a common symptom of hyperthyroidism, which is characterized by an excess secretion of thyroid hormone. This increased metabolic rate can lead to weight loss despite normal or increased appetite. Bradycardia (slow heart rate), cold intolerance, and lethargy are more commonly associated with hypothyroidism, where there is an insufficient production of thyroid hormone. Therefore, choices B, C, and D are incorrect in the context of hypersecretion of thyroid hormone.
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