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: C

Rationale: The function of the alveoli in the lungs is to exchange gases. Oxygen from the inhaled air diffuses into the bloodstream, while carbon dioxide from the bloodstream diffuses into the alveoli to be exhaled. This exchange process is crucial for maintaining proper oxygen levels in the blood and removing carbon dioxide, a waste product. Option A is incorrect because the alveoli do not absorb oxygen but facilitate its exchange. Option B is incorrect because while the alveoli do remove carbon dioxide, their primary function is gas exchange. Option D is incorrect as the alveoli do not regulate blood pressure but are essential for gas exchange in the respiratory system.

Correct Answer: B

Rationale: The correct answer is B: Larynx. The larynx is an organ of the respiratory system responsible for producing sound and protecting the trachea during swallowing. It is located in the throat region and contains vocal cords. The brain (A) is part of the nervous system, not the respiratory system. The urethra (C) is part of the urinary system, and the pancreas (D) is part of the digestive system. Therefore, the larynx is the only choice directly related to the respiratory system.

Correct Answer: A

Rationale: The correct answer is A: To filter blood and remove old red blood cells. The spleen is an important organ in the lymphatic system responsible for filtering blood, removing old or damaged red blood cells, and storing platelets. It also plays a role in immune function by producing antibodies and storing lymphocytes. Choices B, C, and D are incorrect as the spleen's main functions are related to blood filtration and immune response, not lymphocyte production, vitamin storage, or temperature regulation.

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.