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ATI Anatomy and Physiology Online Practice
1. A parietal layer of a serous membrane lines cavities, whereas a visceral layer of a serous membrane covers organs.
- A. covers organs; lines cavities
- B. lines cavities; covers organs
- C. secretes serous fluid; secretes mucus
- D. secretes mucus; secretes a serous fluid
Correct answer: B
Rationale: In serous membranes, the parietal layer lines the cavities, providing support and protection, while the visceral layer covers the organs, reducing friction and allowing them to move freely. Therefore, the correct answer is 'lines cavities; covers organs.' Choices C and D are incorrect because serous membranes do not secrete mucus; instead, they secrete a watery serous fluid. Choice A is incorrect as it reverses the functions of the parietal and visceral layers in relation to organs and cavities.
2. In negative feedback mechanisms, changes away from the normal state
- A. stimulate changes in the same direction
- B. inhibit all body reactions
- C. stimulate changes in the opposite direction
- D. stimulate a reduction in all body requirements
Correct answer: C
Rationale: In negative feedback mechanisms, changes away from the normal state stimulate changes in the opposite direction. This is a fundamental concept in biological systems where the response to a stimulus opposes the initial change, helping to maintain homeostasis. Choice A is incorrect because negative feedback does not stimulate changes in the same direction. Choice B is incorrect because negative feedback does not inhibit all body reactions, but rather specific responses. Choice D is incorrect because negative feedback does not stimulate a reduction in all body requirements, but rather adjusts specific functions to restore balance.
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. Calcium concentration in the blood is controlled by which of the following glands?
- A. Hypothalamus gland
- B. Thyroid gland
- C. Pituitary gland
- D. Parathyroid glands
Correct answer: D
Rationale: The correct answer is Parathyroid glands. The parathyroid glands are responsible for regulating calcium levels in the blood by secreting parathyroid hormone (PTH). PTH helps increase calcium levels in the blood when they are too low. The other glands listed, such as the Hypothalamus, Thyroid, and Pituitary glands, do not directly control calcium concentration in the blood.
5. Which of the following electrolytes plays an essential role in the clotting of blood?
- A. sodium
- B. magnesium
- C. calcium
- D. potassium
Correct answer: C
Rationale: Calcium plays an essential role in the clotting of blood by being involved in several steps of the coagulation process. It is necessary for the conversion of prothrombin to thrombin, which is a crucial step in forming blood clots. Sodium, magnesium, and potassium do not directly participate in the clotting cascade and are not associated with the coagulation process. Therefore, the correct answer is calcium.
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