ATI TEAS 7
ati teas 7 science
1. Which hormone, produced by the thyroid gland, plays a key role in regulating calcium levels in the blood by promoting calcium release from bones and increasing calcium reabsorption in the kidneys?
- A. Calcitonin
- B. Parathyroid hormone (PTH)
- C. Thyroxine
- D. Insulin
Correct answer: A
Rationale: Calcitonin, produced by the thyroid gland, is responsible for regulating calcium levels in the blood. It works by decreasing blood calcium levels through two main mechanisms: promoting calcium uptake by bones and decreasing calcium reabsorption in the kidneys. Parathyroid hormone (PTH), on the other hand, increases blood calcium levels by promoting calcium release from bones and increasing calcium absorption in the intestines. Thyroxine, another thyroid hormone, primarily regulates metabolism and has no direct influence on calcium levels. Insulin, produced by the pancreas, is involved in regulating blood sugar levels and is not related to calcium homeostasis.
2. What is the scientific term for the involuntary rhythmic contraction and relaxation of the heart muscle?
- A. Peristalsis
- B. Myogenesis
- C. Myocardial contractility
- D. Systole and diastole
Correct answer: D
Rationale: The correct answer is D: Systole and diastole. Systole and diastole are the two phases of the cardiac cycle where the heart muscle contracts (systole) and relaxes (diastole) rhythmically to pump blood throughout the body. This rhythmic process ensures proper blood circulation by pumping blood to the lungs and the rest of the body. Peristalsis, on the other hand, refers to the involuntary constriction and relaxation of the muscles in the gastrointestinal tract, aiding in the movement of food and waste. Myogenesis is the process of muscle tissue formation, and myocardial contractility pertains to the heart muscle's ability to contract efficiently.
3. How can the periodic table be used to predict the charge of an ion formed by an element?
- A. Look for elements with similar atomic weights.
- B. Identify the group number, which corresponds to the typical ionic charge.
- C. Calculate the difference between protons and electrons.
- D. Analyze the element's position within the period.
Correct answer: B
Rationale: The group number of an element on the periodic table corresponds to the number of valence electrons it has. Elements in the same group tend to form ions with the same charge. For example, elements in Group 1 typically form ions with a +1 charge, while elements in Group 17 typically form ions with a -1 charge. Therefore, by identifying the group number of an element, one can predict the typical ionic charge it will form. Choices A, C, and D are incorrect because predicting the charge of an ion is mainly based on the element's position in the periodic table, particularly the group number, which indicates the number of valence electrons and the typical ionic charge it may form.
4. Which dome-shaped muscular structure separates the chest cavity from the abdominal cavity?
- A. Diaphragm
- B. Sternum
- C. Pericardium
- D. Trachea
Correct answer: A
Rationale: The diaphragm is the correct answer. It is a dome-shaped muscular structure that separates the chest cavity from the abdominal cavity. The diaphragm plays a crucial role in breathing by contracting and relaxing to change thoracic volume during inhalation and exhalation. The sternum is a flat bone in the center of the chest and is not the structure that separates the chest and abdominal cavities. The pericardium is a membrane that surrounds the heart, not involved in separating cavities. The trachea is the windpipe that connects the larynx to the bronchi and is not the structure that separates the chest and abdominal cavities.
5. What is the role of surfactant in the respiratory system?
- A. To trap dust particles
- B. To increase lung compliance
- C. To produce mucus
- D. To generate oxygen during respiration
Correct answer: B
Rationale: The correct answer is B: To increase lung compliance. Surfactant is a substance produced by type II alveolar cells in the lungs that reduces surface tension in the alveoli. This reduction in surface tension helps to increase lung compliance, making it easier for the lungs to expand and contract during breathing. Improved lung compliance is essential for efficient gas exchange in the respiratory system, facilitating oxygen uptake and carbon dioxide removal. Choices A, C, and D are incorrect because surfactant does not trap dust particles, produce mucus, or generate oxygen during respiration. Instead, its primary function lies in reducing surface tension to prevent alveolar collapse and improve lung compliance for optimal gas exchange.
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