Anatomy HESI A2 Practice Test

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: 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: To store urine. The urinary bladder serves as a reservoir for storing urine before it is eliminated from the body. It collects and holds urine until a person is ready to excrete it. The other choices are incorrect because: A) The kidneys filter waste from the blood, not the bladder. C) Fluid balance is primarily regulated by the kidneys and hormones, not the bladder. D) Waste removal from the body is mainly carried out by the kidneys and excretory system, not the bladder.

Correct Answer: B

Rationale: The correct answer is B: Cerebrum. The cerebrum, specifically the motor cortex located in the frontal lobe, controls voluntary movement. It sends signals to the muscles via the spinal cord. The cerebellum (A) is responsible for coordination and balance, not voluntary movement. The brainstem (C) controls basic life functions like breathing and heart rate, while the medulla oblongata (D) regulates vital functions such as blood pressure and breathing, not voluntary movement. Therefore, the cerebrum is the correct choice for controlling voluntary movement.

Correct Answer: B

Rationale: The correct answer is B: To store and concentrate bile. The gallbladder acts as a reservoir for bile produced by the liver, which is then released into the small intestine to aid in digestion. Bile helps emulsify fats for better absorption. Choices A, C, and D are incorrect as the gallbladder does not produce bile (the liver does), detoxify harmful substances, or directly break down fats. The primary function of the gallbladder is to store and concentrate bile for efficient digestion.