HESI A2 Anatomy and Physiology 2023

Correct Answer: C

Rationale: The correct answer is C: Occipital lobe. The occipital lobe is responsible for processing visual information as it contains the primary visual cortex. This part of the brain interprets visual stimuli received from the eyes. Other choices are incorrect because: A: Frontal lobe is primarily involved in higher-level thinking, decision-making, and motor functions. B: Parietal lobe processes sensory information, spatial awareness, and perception of stimuli like touch and pressure. D: Temporal lobe plays a role in auditory processing, memory, and language comprehension.

Correct Answer: B

Rationale: The correct answer is B: Parathyroid hormone. Parathyroid hormone is produced by the parathyroid glands and plays a crucial role in regulating calcium levels in the blood. It does so by increasing calcium absorption in the intestines, reabsorption in the kidneys, and release from bones. Insulin (choice A) regulates blood sugar, not calcium. Cortisol (choice C) is a stress hormone and does not directly affect calcium levels. Melatonin (choice D) regulates sleep-wake cycles and does not play a role in calcium regulation. Therefore, the correct choice is B as it directly influences calcium levels in the blood.

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for balance and coordination as it receives sensory information from the inner ear and muscles to control movement. It coordinates muscle actions and maintains posture. The cerebrum (B) is responsible for higher brain functions, the medulla oblongata (C) controls basic life functions like breathing and heart rate, and the hypothalamus (D) regulates body temperature, hunger, and thirst. Thus, the cerebellum is the most appropriate choice for balance and coordination.

Correct Answer: C

Rationale: The correct answer is C: Cortisol. Cortisol is a hormone released by the adrenal glands in response to stress. It helps regulate metabolism, immune response, and blood pressure during stressful situations. Insulin (A) is involved in regulating blood sugar levels, not the stress response. Adrenaline (B) is also known as epinephrine and is involved in the fight-or-flight response, which is part of the stress response. Melatonin (D) is a hormone that regulates sleep-wake cycles and is not directly related to the stress response.

Correct Answer: A

Rationale: The correct answer is A: Pancreas. The pancreas is responsible for producing insulin, a hormone that helps regulate blood sugar levels. It contains clusters of cells called islets of Langerhans, which specifically produce insulin. The liver (B) is involved in storing glucose and producing bile, not insulin. The gallbladder (C) stores bile produced by the liver and aids in digestion, not insulin production. The kidneys (D) filter blood and regulate fluid balance, but do not produce insulin. Therefore, the pancreas is the organ responsible for insulin production in the body.