HESI A2
Anatomy and Physiology Hesi A2 Practice Test
1. What is the primary function of platelets?
- A. To fight infections
- B. To clot blood
- C. To carry oxygen
- D. To transport nutrients
Correct answer: B
Rationale: The primary function of platelets, or thrombocytes, is to clot blood. Platelets play a crucial role in hemostasis by forming clots to prevent excessive bleeding when injuries occur. They are not directly involved in fighting infections, carrying oxygen, or transporting nutrients. Therefore, the correct answer is B.
2. Which hormone is involved in regulating the sleep-wake cycle?
- A. Insulin
- B. Melatonin
- C. Cortisol
- D. Thyroxine
Correct answer: B
Rationale: The correct answer is B: Melatonin. Melatonin, produced by the pineal gland, is the hormone involved in regulating the sleep-wake cycle. It plays a crucial role in signaling the body that it is time to sleep and is influenced by light exposure. Melatonin levels typically rise in the evening, promoting sleep, and decrease in the morning, helping in waking up. Choice A, Insulin, is involved in regulating blood sugar levels, not the sleep-wake cycle. Choice C, Cortisol, is a stress hormone that helps regulate metabolism and immune response but is not primarily involved in the sleep-wake cycle. Choice D, Thyroxine, is a hormone produced by the thyroid gland that regulates metabolism, growth, and development, but it is not directly involved in regulating the sleep-wake cycle.
3. Which type of muscle is under voluntary control?
- A. Smooth muscle
- B. Cardiac muscle
- C. Skeletal muscle
- D. Striated muscle
Correct answer: C
Rationale: The correct answer is C: Skeletal muscle. Skeletal muscle is under voluntary control, allowing individuals to consciously regulate its contractions for movement. Examples of skeletal muscle control include actions like walking, running, and lifting weights. Smooth muscle (choice A) and cardiac muscle (choice B) are both involuntary muscles, meaning they are not under conscious control. While skeletal muscle is striated (choice D), striated muscle is a broader category that includes both voluntary (skeletal) and involuntary (cardiac) muscles.
4. Which bone does not articulate with any other bone?
- A. Femur
- B. Hyoid
- C. Radius
- D. Tibia
Correct answer: B
Rationale: The correct answer is the Hyoid bone. The hyoid bone is distinctive as it does not directly articulate with any other bone in the body. Instead, it is held in place by muscles and ligaments, playing a crucial role in supporting the tongue and providing attachment points for various muscles involved in swallowing and speech. The other choices, Femur, Radius, and Tibia, all articulate with other bones in the body. The femur articulates with the hip bone, the radius articulates with the ulna and other bones in the wrist, and the tibia articulates with the femur and fibula.
5. Which nutrients are important for bone health?
- A. Vitamin D
- B. Calcium and phosphorus
- C. Iron and zinc
- D. Magnesium and sodium
Correct answer: B
Rationale: Calcium and phosphorus are crucial nutrients for bone health as they are essential minerals required for bone strength, density, and various body functions. Adequate intake of calcium and phosphorus through the diet is important for maintaining healthy bones and preventing conditions like osteoporosis. Vitamin D helps with calcium absorption, but it is not the main nutrient responsible for bone health. Iron and zinc are important for other bodily functions, not specifically bone health. Magnesium and sodium, while important for overall health, are not as directly linked to bone health as calcium and phosphorus.
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