HESI A2 Anatomy and Physiology 2023

Correct Answer: B

Rationale: The correct answer is B: Thyroid gland. The thyroid gland produces hormones such as thyroxine (T4) and triiodothyronine (T3), which regulate metabolism by controlling the body's energy production and utilization. The pituitary gland (A) regulates various other hormones but not specifically metabolism. The adrenal gland (C) produces hormones like cortisol and adrenaline, which are involved in stress response, not metabolism. The pineal gland (D) produces melatonin, which regulates sleep-wake cycles, not metabolism. Therefore, the thyroid gland is the correct answer as it directly controls metabolic functions.

Correct Answer: A

Rationale: The primary function of the cardiovascular system is to transport oxygen and nutrients to cells throughout the body. This is achieved through the circulation of blood by the heart and blood vessels. Oxygen is vital for cellular respiration, and nutrients are essential for cell function. Regulating body temperature is primarily the role of the integumentary and nervous systems, not the cardiovascular system. Removing waste products is mainly the function of the excretory system. Hormone production is primarily controlled by the endocrine system, not the cardiovascular system. Therefore, choice A is correct as it directly aligns with the main purpose of the cardiovascular system.

Correct Answer: C

Rationale: The correct answer is C: Cortisol. Cortisol is a hormone released by the adrenal glands in response to stress. It helps regulate metabolism, immune response, and blood pressure during stressful situations. Insulin (A) is involved in regulating blood sugar levels, not the stress response. Adrenaline (B) is also known as epinephrine and is involved in the fight-or-flight response, which is part of the stress response. Melatonin (D) is a hormone that regulates sleep-wake cycles and is not directly related to the stress response.

Correct Answer: B

Rationale: The correct answer is B: Hinge joint. The elbow joint is a hinge joint because it allows movement in one plane, similar to a door hinge. It primarily allows flexion and extension movements. A ball and socket joint (A) allows a wider range of motion in multiple planes. A pivot joint (C) allows rotation around a central axis. A saddle joint (D) allows movement in multiple directions with a greater range of motion compared to a hinge joint.

Correct Answer: B

Rationale: The correct answer is B: Support and protection. The skeletal system provides structural support for the body and protects internal organs. It also helps with movement, stores minerals, and produces blood cells. Choices A, C, and D are incorrect because the production of red blood cells occurs in the bone marrow, secretion of hormones is primarily the function of the endocrine system, and regulation of body temperature is controlled by the nervous system and other mechanisms, not the skeletal system.