Quizlet HESI A2 Anatomy and Physiology

Correct Answer: B

Rationale: Platelets play a crucial role in blood clotting. When a blood vessel is damaged, platelets adhere to the site to form a plug to stop bleeding. This process is essential for wound healing and preventing excessive blood loss. Platelets do not transport oxygen (A), fight infection (C), or transport nutrients (D). Oxygen is carried by red blood cells, immune cells fight infection, and nutrients are transported by plasma and other blood components.

Correct Answer: B

Rationale: The correct answer is B: Vitamin D. Vitamin D is necessary for the absorption of calcium in the intestines. It helps regulate calcium and phosphorus levels in the blood, promoting bone health. Vitamin C (A) plays a role in collagen synthesis, not calcium absorption. Vitamin A (C) is important for vision and immune function, not calcium absorption. Vitamin K (D) is crucial for blood clotting, not calcium absorption.

Correct Answer: A

Rationale: The correct answer is A: Transporting oxygen. Hemoglobin is a protein in red blood cells that binds to oxygen in the lungs and carries it to tissues throughout the body. This process is essential for cellular respiration and energy production. The other choices are incorrect because hemoglobin does not primarily function in carrying nutrients, clotting blood, or removing carbon dioxide from the blood. Transporting oxygen is the main and crucial role of hemoglobin in the blood.

Correct Answer: B

Rationale: The correct answer is B: Heart. The heart is not a component of the central nervous system (CNS) as it is part of the cardiovascular system. The CNS consists of the brain, spinal cord, and retina. The brain controls cognitive functions, the spinal cord transmits nerve signals, and the retina is a part of the visual system. Choice B is incorrect as the heart's function is to pump blood and is not involved in CNS functions.

Correct Answer: B

Rationale: The correct answer is B: To protect the body from external damage. The skin acts as a physical barrier, preventing harmful substances from entering the body and protecting internal organs. It also helps regulate body temperature to some extent, but that is not its primary function. The skin does not produce vitamin D; this is mainly done by the liver and kidneys. Red blood cells are produced in the bone marrow, not the skin.