HESI A2 Anatomy and Physiology 2023

Correct Answer: B

Rationale: During the fight-or-flight response, the body needs to prepare for immediate action. Adrenaline, also known as epinephrine, is the hormone released by the adrenal glands in response to stress or danger. Adrenaline triggers physiological changes such as increased heart rate, blood flow to muscles, and heightened awareness to help the body react quickly. Insulin is involved in regulating blood sugar levels, not the fight-or-flight response. Thyroxine plays a role in metabolism, while cortisol is released in response to stress but is not the primary hormone involved in the fight-or-flight response.

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for controlling balance and coordination. It receives information from the sensory systems, such as the inner ear and visual system, and integrates this information to coordinate smooth movements. The cerebrum (B) is mainly involved in higher brain functions like thinking and problem-solving. The medulla oblongata (C) controls vital functions such as breathing and heart rate. The brainstem (D) is responsible for basic life functions like breathing and consciousness. Thus, the cerebellum is the specific region of the brain that directly controls balance and coordination.

Correct Answer: B

Rationale: The correct answer is B: Skin. The skin is the largest organ in the human body by surface area, covering about 20 square feet on average. It serves as a protective barrier against external elements and plays a crucial role in regulating body temperature. The liver (A), brain (C), and heart (D) are important organs, but they are not the largest in terms of size or surface area. Therefore, the correct choice is the skin.

Correct Answer: B

Rationale: The correct answer is B: Adrenaline. Adrenaline, also known as epinephrine, is released by the adrenal glands during the fight or flight response. It increases heart rate, blood flow to muscles, and alertness to prepare the body for emergency situations. Cortisol (A) is a stress hormone but not directly involved in the immediate fight or flight response. Thyroxine (C) regulates metabolism and growth, not specifically related to fight or flight. Melatonin (D) regulates sleep-wake cycles and is not involved in the fight or flight response.

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.