Anatomy and Physiology Hesi A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. The medulla oblongata is located in the brainstem and is responsible for controlling vital functions such as breathing and heart rate. It contains the respiratory center that regulates breathing and the cardiac center that controls heart rate. The cerebrum (A) is involved in higher brain functions such as thinking and voluntary movements, not in controlling basic bodily functions. The cerebellum (C) is responsible for coordination and balance, not for regulating breathing or heart rate. The hypothalamus (D) plays a role in regulating body temperature, hunger, and thirst, but not specifically in controlling breathing and heart rate.

Correct Answer: B

Rationale: The correct answer is B: To detoxify harmful substances. The liver plays a crucial role in metabolism by detoxifying harmful substances such as drugs and alcohol. It metabolizes these substances into less harmful compounds for elimination from the body. Other choices are incorrect because: A: The liver produces bile to aid in digestion, not directly related to metabolism. C: While the liver stores glucose in the form of glycogen, it is not its primary role in metabolism. D: Insulin is produced by the pancreas, not the liver, to regulate blood sugar levels, not directly related to liver's role in metabolism.

Correct Answer: D

Rationale: The correct answer is D: Larynx. The larynx is an organ of the respiratory system because it plays a crucial role in producing sound and facilitating the passage of air to the lungs. It contains the vocal cords and is located in the throat. The other choices (A: Pancreas, B: Brain, C: Urethra) are not part of the respiratory system. The pancreas is part of the digestive system, the brain is part of the nervous system, and the urethra is part of the urinary system.

Correct Answer: B

Rationale: The correct answer is B: Melatonin. Melatonin is a hormone produced by the pineal gland that plays a crucial role in regulating the sleep-wake cycle. It is released in response to darkness and helps signal to the body that it is time to sleep. Melatonin levels increase at night, promoting sleep, and decrease during the day, promoting wakefulness. A: Insulin is a hormone that helps regulate blood sugar levels, not the sleep-wake cycle. C: Cortisol is a stress hormone involved in the body's response to stress and is not directly related to the sleep-wake cycle. D: Thyroxine is a hormone produced by the thyroid gland that regulates metabolism and energy levels, not the sleep-wake cycle.

Correct Answer: C

Rationale: The motor cortex is located in the front portion of the parietal lobe. This area is specifically known as the primary motor cortex, which is responsible for planning, controlling, and executing voluntary movements. It sends signals to the muscles to initiate movement. Option A (back of the head) is incorrect as that area is primarily related to visual processing. Option B (top middle portion of the parietal lobe) is incorrect as that area is more associated with somatosensory processing. Option D (around the auditory cortex) is incorrect as the auditory cortex is responsible for processing auditory information, not motor functions.