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: Hinge. The elbow joint is a hinge joint because it allows movement in only one plane, similar to a door hinge. It primarily enables flexion and extension movements. A: Ball and socket joints, like the hip joint, allow for a wider range of motion in multiple planes. C: Pivot joints, found in the neck, allow for rotational movements. D: Saddle joints, like the thumb joint, have a more complex shape that permits a variety of movements, but not present at the elbow.

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: A

Rationale: The primary function of the hypothalamus is to regulate body balance and thermoregulation. It maintains homeostasis by controlling various physiological processes such as body temperature, blood pressure, and electrolyte balance. It also plays a role in regulating hormonal functions through the pituitary gland. Choices B, C, and D are incorrect because hunger, thirst, sleep, circadian rhythms, and voluntary movements are primarily controlled by other brain regions such as the amygdala, pineal gland, and motor cortex, respectively.

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.