Anatomy HESI A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Semicircular canals. These structures in the inner ear are responsible for detecting rotational movement and maintaining balance. The semicircular canals contain fluid that moves in response to head movements, stimulating hair cells that send signals to the brain about the body's position in space. A: The cochlea is responsible for hearing, not balance. C: Ossicles are tiny bones in the middle ear that transmit sound vibrations to the cochlea. D: The Eustachian tube helps equalize pressure in the middle ear and is not directly related to balance. In summary, the semicircular canals are crucial for maintaining balance by detecting rotational movements, while the other structures mentioned are primarily involved in hearing or pressure regulation.

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: Mouth. Digestion begins in the mouth where food is mechanically broken down by chewing and chemically broken down by enzymes in saliva. This initial process prepares food for further digestion in the stomach and small intestine. The stomach (A) primarily functions to further break down food through acid and enzymes. The small intestine (C) is where the majority of nutrients are absorbed, not where digestion begins. The esophagus (D) is responsible for transporting food from the mouth to the stomach, but it does not participate in the actual digestion process.

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.

Correct Answer: A

Rationale: The correct answer is A: Vitamin A. Vitamin A is essential for vision as it plays a crucial role in the function of the retina and helps maintain a healthy cornea. It is also important for skin health by promoting skin cell growth and repair. Vitamin C (B) is important for immune function and collagen synthesis, not specifically for vision or skin health. Vitamin D (C) is crucial for bone health and immune function. Vitamin E (D) is an antioxidant that helps protect cells from damage, but it is not specifically essential for vision or skin health.