Anatomy HESI A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. This part of the brain is located in the brainstem and is responsible for regulating essential functions like breathing and heart rate. The medulla oblongata contains centers that control autonomic functions, ensuring that these processes occur involuntarily and without conscious effort. The other choices, A (Cerebrum), C (Cerebellum), and D (Hypothalamus), are not specifically involved in regulating breathing and heart rate. The cerebrum is responsible for higher brain functions, the cerebellum is involved in coordination and balance, and the hypothalamus controls body temperature, hunger, and thirst regulation.

Correct Answer: B

Rationale: The correct answer is B: To transport oxygen. Hemoglobin is a protein in red blood cells that binds to oxygen in the lungs and carries it to tissues throughout the body. This process is essential for cellular respiration and energy production. Choice A is incorrect because fighting infections is the role of the immune system, not hemoglobin. Choice C is incorrect as hemoglobin primarily carries oxygen, not carbon dioxide. Choice D is incorrect as hemoglobin binds and releases oxygen to tissues, rather than storing it.

Correct Answer: B

Rationale: White blood cells' main function is to fight infections. They are part of the immune system, detecting and destroying pathogens like bacteria and viruses. They do not carry oxygen (A), nutrients (C), or remove waste products (D). White blood cells play a crucial role in protecting the body from harmful invaders, making choice B the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Adrenal cortex. During stress, the adrenal cortex secretes cortisol and aldosterone, which help the body respond to stress. The parathyroid gland (A) regulates calcium levels, not stress hormones. The posterior pituitary gland (C) releases hormones like oxytocin and vasopressin, not stress hormones. The hypothalamus (D) plays a role in regulating the stress response by signaling the adrenal cortex to release stress hormones.

Correct Answer: B

Rationale: The correct answer is B: Detoxifying harmful substances. The liver plays a crucial role in filtering and detoxifying harmful substances like drugs, alcohol, and metabolic waste products. It metabolizes these substances to make them less harmful for elimination from the body. This function is essential for maintaining overall health and preventing damage to other organs. Incorrect Choices: A: Producing insulin - The pancreas is responsible for producing insulin, not the liver. C: Digesting food - The liver produces bile that aids in digestion, but its primary role is not digesting food. D: Storing energy - While the liver does store glycogen as an energy reserve, its primary role is not storing energy.