HESI A2 Anatomy and Physiology 2023

Correct Answer: B

Rationale: The correct answer is B: Glomerulus. The glomerulus is a network of tiny blood vessels in the nephron that filters blood to form urine. It acts as the initial filtration site in the kidney, allowing waste products and excess substances to be removed from the blood. Bowman's capsule surrounds the glomerulus and collects the filtered fluid. The loop of Henle is responsible for reabsorbing water and electrolytes. While the nephron is the functional unit of the kidney, the glomerulus specifically performs the blood filtering process crucial for urine formation.

Correct Answer: C

Rationale: The correct answer is C: Front portion of the parietal lobe. This area is known as the primary motor cortex, responsible for planning, control, and execution of voluntary movements. It receives input from other brain regions involved in movement. Choices A, B, and D are incorrect because the top, middle portion of the parietal lobe is involved in sensory processing, the back of the head is associated with the occipital lobe responsible for vision, and around the auditory cortex is involved in processing auditory information, respectively.

Correct Answer: B

Rationale: The correct answer is B: Thyroid gland. The thyroid gland produces hormones such as thyroxine (T4) and triiodothyronine (T3), which regulate metabolism by controlling the body's energy production and utilization. The pituitary gland (A) regulates various other hormones but not specifically metabolism. The adrenal gland (C) produces hormones like cortisol and adrenaline, which are involved in stress response, not metabolism. The pineal gland (D) produces melatonin, which regulates sleep-wake cycles, not metabolism. Therefore, the thyroid gland is the correct answer as it directly controls metabolic functions.

Correct Answer: B

Rationale: The correct answer is B: To produce bile and detoxify substances. The liver plays a crucial role in producing bile, which aids in digestion by breaking down fats. It also detoxifies harmful substances in the body. Choices A, C, and D are incorrect because the liver does not primarily filter blood, produce insulin, or produce red blood cells. Filtering blood is mainly done by the kidneys, insulin is produced by the pancreas, and red blood cells are produced in the bone marrow.

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for controlling balance and coordination. It receives information from the sensory systems, such as the inner ear and visual system, and integrates this information to coordinate smooth movements. The cerebrum (B) is mainly involved in higher brain functions like thinking and problem-solving. The medulla oblongata (C) controls vital functions such as breathing and heart rate. The brainstem (D) is responsible for basic life functions like breathing and consciousness. Thus, the cerebellum is the specific region of the brain that directly controls balance and coordination.