HESI A2 Anatomy and Physiology Quizlet

Correct Answer: B

Rationale: The correct answer is B: Glucagon. When blood glucose levels are low, the pancreas releases glucagon to stimulate the liver to convert stored glycogen into glucose, raising blood sugar levels. Insulin (Choice A) is released in response to high blood glucose, promoting glucose uptake by cells. Cortisol (Choice C) and adrenaline (Choice D) are stress hormones and not directly involved in regulating blood glucose levels.

Correct Answer: A

Rationale: The main function of the circulatory system is to transport oxygen and nutrients to all cells in the body. This is achieved through the blood vessels and the pumping action of the heart. Oxygen is necessary for cellular respiration, while nutrients are essential for cell growth and metabolism. Without these, cells cannot function properly, leading to organ failure and ultimately, death. Options B, C, and D are incorrect because although the circulatory system indirectly helps remove waste products, regulate body temperature, and protect organs, these are not its primary functions.

Correct Answer: B

Rationale: The correct answer is B: Lens. The lens is responsible for focusing light onto the retina by adjusting its shape to bend the light rays. The cornea (A) primarily helps in refracting light, while the pupil (C) and iris (D) are involved in regulating the amount of light entering the eye, not in focusing light onto the retina. Therefore, the lens is the correct choice as it plays a crucial role in the process of focusing light onto the retina.

Correct Answer: B

Rationale: The correct answer is B: Pivot joint. Pivot joints allow for rotational movement around a single axis. This type of joint is found in the neck, allowing the head to rotate side to side. Hinge joints (choice A) allow movement in one plane like the elbow. Ball and socket joints (choice C) allow for a wide range of movement in multiple directions like the hip and shoulder. Saddle joints (choice D) allow for movement in two axes like the thumb. Therefore, the correct answer is pivot joint as it specifically allows for rotational movement around a single axis.

Correct Answer: C

Rationale: The correct answer is C: Veins. Veins carry deoxygenated blood back to the heart. They have valves to prevent backflow and are thin-walled. Arteries (A) carry oxygenated blood away from the heart. Capillaries (B) are tiny vessels where oxygen exchange occurs. Lymphatic vessels (D) transport lymph, not blood.