HESI A2 Anatomy and Physiology Quizlet

Correct Answer: B

Rationale: The correct answer is B: Pivot joint. Pivot joints allow for rotational movement around a single axis. This type of joint is found in the neck, allowing the head to rotate side to side. Hinge joints (choice A) allow movement in one plane like the elbow. Ball and socket joints (choice C) allow for a wide range of movement in multiple directions like the hip and shoulder. Saddle joints (choice D) allow for movement in two axes like the thumb. Therefore, the correct answer is pivot joint as it specifically allows for rotational movement around a single axis.

Correct Answer: B

Rationale: The correct answer is B: Pivot joint. In the neck, the pivot joint allows for rotational movement by articulating the first and second cervical vertebrae. This joint structure enables the head to rotate from side to side. A: Hinge joint is incorrect because it allows movement in only one plane, like the elbow or knee. C: Ball and socket joint allows for a wide range of motion in multiple directions, like the hip or shoulder. D: Saddle joint allows for movement in two planes, like the thumb joint. The specific rotational movement in the neck is facilitated by the pivot joint, making it the correct choice.

Correct Answer: B

Rationale: The correct answer is B: Hypothalamus. The hypothalamus plays a crucial role in regulating body temperature through its control over thermoregulation processes. It receives input from temperature receptors in the body and initiates responses to maintain a stable internal temperature. The other choices are incorrect because the cerebellum is primarily responsible for coordination and balance, the medulla oblongata controls vital functions like breathing and heart rate, and the pineal gland regulates sleep-wake cycles through the secretion of melatonin.

Correct Answer: A

Rationale: The correct answer is A: Hippocampus. The hippocampus is involved in memory formation as it plays a crucial role in the consolidation of short-term memory into long-term memory. It also helps in spatial navigation and declarative memory. The amygdala (choice B) is associated with emotions and emotional memories, not memory formation. The cerebellum (choice C) is primarily responsible for motor coordination, not memory. The medulla oblongata (choice D) is involved in vital autonomic functions like breathing and heart rate, not memory.

Correct Answer: A

Rationale: The correct answer is A: Melatonin. Melatonin is a hormone produced by the pineal gland that plays a key role in regulating the sleep-wake cycle. It helps control the body's internal clock and signals the brain when it's time to sleep. Melatonin levels typically rise in the evening, promoting sleep, and decrease in the morning, promoting wakefulness. Summary of incorrect choices: B: Insulin - Insulin is a hormone that regulates blood sugar levels, not the sleep-wake cycle. C: Cortisol - Cortisol is a stress hormone that helps regulate metabolism and immune response, but it does not directly control the sleep-wake cycle. D: Thyroxine - Thyroxine is a hormone produced by the thyroid gland that regulates metabolism, growth, and development, but it is not directly involved in the sleep-wake cycle regulation.