Anatomy and Physiology Hesi A2 Practice Test

Correct Answer: B

Rationale: The correct answer is B: Spinal cord. The spinal cord is part of the peripheral nervous system, not the central nervous system. The central nervous system consists of the brain and spinal cord, while the peripheral nervous system includes nerves outside of the brain and spinal cord. The retina (A) is part of the central nervous system as it is an extension of the brain, responsible for processing visual information. The brain (C) is obviously part of the central nervous system as the main control center of the body. The heart (D) is not part of the central nervous system; it is part of the cardiovascular system.

Correct Answer: B

Rationale: The correct answer is B: Hyoid. The hyoid bone is the only bone in the human body that does not directly articulate with any other bone. It is a U-shaped bone located in the neck, suspended by ligaments and muscles. Its unique position and function in supporting the tongue and larynx make it distinct from the other choices. The femur (A), radius (C), and tibia (D) are all long bones that articulate with neighboring bones at their respective joints, such as the hip, elbow, and knee joints, respectively. The hyoid bone's isolated location and lack of direct articulation with other bones set it apart as the correct choice.

Correct Answer: B

Rationale: The correct answer is B: epidermis. The epidermis is the outermost layer of the skin, serving as a protective barrier. It consists of several layers of cells, including keratinocytes which provide waterproofing and protection. The dermis (choice A) is the layer beneath the epidermis, providing structural support. Subcutaneous tissue (choice C) and hypodermis (choice D) are the deepest layers of the skin, mainly composed of fat cells and connective tissue, playing a role in insulation and cushioning. Therefore, the epidermis is the correct choice as it directly interacts with the external environment and is responsible for protecting the body.

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. The medulla oblongata is located in the brainstem and is responsible for controlling vital functions such as breathing and heart rate. It contains the respiratory center that regulates breathing and the cardiac center that controls heart rate. The cerebrum (A) is involved in higher brain functions such as thinking and voluntary movements, not in controlling basic bodily functions. The cerebellum (C) is responsible for coordination and balance, not for regulating breathing or heart rate. The hypothalamus (D) plays a role in regulating body temperature, hunger, and thirst, but not specifically in controlling breathing and heart rate.

Correct Answer: B

Rationale: The correct answer is B: To detoxify harmful substances. The liver plays a crucial role in metabolism by detoxifying harmful substances such as drugs and alcohol. It metabolizes these substances into less harmful compounds for elimination from the body. Other choices are incorrect because: A: The liver produces bile to aid in digestion, not directly related to metabolism. C: While the liver stores glucose in the form of glycogen, it is not its primary role in metabolism. D: Insulin is produced by the pancreas, not the liver, to regulate blood sugar levels, not directly related to liver's role in metabolism.