HESI A2 Anatomy and Physiology Practice Exam

Correct Answer: D

Rationale: The correct answer is D: Cilia. Cilia are part of the body's primary defense system in the respiratory tract, not the secondary defense system. The secondary defense system involves immune cells like macrophages, leukocytes, and T cells that work to target and eliminate pathogens. Cilia primarily function to trap and remove foreign particles in the airways as part of the body's physical barrier against infections. Therefore, cilia are not considered part of the secondary defense system, making choice D the correct answer.

Correct Answer: A

Rationale: The correct answer is A: When they block a duct. Gallstones cause issues when they obstruct the flow of bile from the gallbladder through the bile ducts. This blockage can lead to severe pain, inflammation, infection, and potentially life-threatening complications. Choices B and C focus on the composition of gallstones, which may not always correlate with symptom severity. Choice D is incorrect because gallstones dissolving can actually relieve symptoms rather than cause problems.

Correct Answer: C

Rationale: The rotator cuff helps stabilize the humerus and scapula during shoulder movements. It consists of muscles and tendons that surround the shoulder joint, providing support and stability. Choice A (Radius and humerus) is incorrect as the radius is not part of the shoulder joint. Choice B (Scapula and clavicle) is incorrect because the clavicle is not directly stabilized by the rotator cuff. Choice D (Ulna and radius) is incorrect as these bones are not part of the shoulder joint and are not stabilized by the rotator cuff. Therefore, choice C (Humerus and scapula) is the correct answer based on the anatomy and function of the rotator cuff in stabilizing the shoulder joint.

Correct Answer: B

Rationale: The correct answer is B because skeletal muscle attaches to bones by tendons, allowing for movement of the body. Tendons are tough connective tissues that anchor muscles to bones. This attachment enables the contraction of skeletal muscles to produce movement at the joints. Choices A, C, and D are incorrect. Skeletal muscle typically makes up around 40-50% of the body's weight, muscle contraction plays a role in temperature regulation through shivering, and skeletal muscles can contract even at rest due to maintaining posture or supporting the body.

Correct Answer: C

Rationale: The correct answer is C because the vertebrae of the spine protect the spinal cord, which is a crucial component of the nervous system. The spinal cord carries electrical signals between the brain and the rest of the body, allowing for communication and coordination of movement and sensation. It is essential for the skeletal system to provide protection to vital nervous system structures. A, B, and D are incorrect: A: While bones do provide support for body position, they do not transmit signals to the brain directly. B: While pain nerves within bones can notify the brain of injuries, this is not the primary way the skeletal system works with the nervous system. D: Bone marrow is responsible for producing blood cells, not nerve cells.