HESI A2 Anatomy and Physiology Quizlet

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: Adrenaline. The adrenal medulla is part of the adrenal glands and is responsible for producing adrenaline, also known as epinephrine. Adrenaline is a hormone that plays a crucial role in the body's fight or flight response, increasing heart rate, blood flow to muscles, and overall alertness in response to stress or danger. Insulin (A) is produced by the pancreas to regulate blood sugar levels, cortisol (C) is produced by the adrenal cortex to regulate stress response and metabolism, and melatonin (D) is produced by the pineal gland to regulate sleep-wake cycles.

Correct Answer: B

Rationale: The correct answer is B: Arteries. Arteries carry oxygenated blood away from the heart due to the contraction of the heart's left ventricle, which pumps blood to the rest of the body. Arteries have thick, muscular walls to withstand the high pressure generated by the heart. Veins (A) carry deoxygenated blood back to the heart, capillaries (C) facilitate exchange of gases and nutrients, and lymphatic vessels (D) transport lymph fluid, not blood.

Correct Answer: B

Rationale: The primary function of the skin in the integumentary system is to protect the body from external damage. The skin acts as a barrier against pathogens, UV radiation, chemicals, and physical injuries. It also helps regulate body temperature, but its main role is protection. Skin does not produce red blood cells (bone marrow does) or hormones (endocrine glands do). Therefore, choice B is correct as it aligns with the main function of the skin.

Correct Answer: D

Rationale: The correct answer is D: Hypothalamus. The hypothalamus is responsible for releasing thyrotrophic-releasing hormone, growth hormone-releasing hormone, and gonadotropin-releasing hormone. The hypothalamus regulates the release of hormones from the pituitary gland, making it a crucial part of the endocrine system. The thymus (A) is involved in immune function, the pituitary gland (B) releases hormones but does not release these specific hormones, and the pineal gland (C) primarily secretes melatonin and regulates sleep-wake cycles, not the hormones mentioned in the question.