HESI A2 Anatomy and Physiology 2023

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: B

Rationale: The correct answer is B: Adrenaline. Adrenaline, also known as epinephrine, is released by the adrenal glands during the fight or flight response. It increases heart rate, blood flow to muscles, and alertness to prepare the body for emergency situations. Cortisol (A) is a stress hormone but not directly involved in the immediate fight or flight response. Thyroxine (C) regulates metabolism and growth, not specifically related to fight or flight. Melatonin (D) regulates sleep-wake cycles and is not involved in the fight or flight response.

Correct Answer: A

Rationale: The correct answer is A: Left ventricle. The left ventricle is the largest and strongest chamber of the heart because it is responsible for pumping oxygen-rich blood to the entire body. It has thicker muscle walls compared to other chambers to generate enough force to push blood through the body's systemic circulation. The left atrium receives oxygenated blood from the lungs, but it does not pump blood out of the heart. The right ventricle pumps blood to the lungs for oxygenation and is not as strong as the left ventricle. The right atrium receives deoxygenated blood from the body and sends it to the right ventricle. Therefore, the left ventricle is the correct answer due to its crucial role in systemic circulation and its muscular structure.

Correct Answer: A

Rationale: Insulin is the correct answer because it is secreted by the pancreas in response to high blood glucose levels. Insulin helps to lower blood glucose levels by promoting the uptake of glucose into cells for energy storage. Glucagon, on the other hand, is secreted by the pancreas to increase blood glucose levels. Somatostatin regulates the release of insulin and glucagon but does not directly lower blood glucose levels. Cortisol is a stress hormone secreted by the adrenal glands and does not play a direct role in lowering blood glucose levels.

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.